diff --git a/examples/parties/client/client.js b/examples/parties/client/client.js
index b2aebab942..3802b2d0ab 100644
--- a/examples/parties/client/client.js
+++ b/examples/parties/client/client.js
@@ -1,16 +1,8 @@
-// XXX I want to collect first/last name when a user signs up by username/password
+// All Tomorrow's Parties -- client
 
 Meteor.subscribe("directory");
 Meteor.subscribe("parties");
 
-Template.page.showCreateDialog = function () {
-  return Session.get("showCreateDialog");
-};
-
-Template.page.showInviteDialog = function () {
-  return Session.get("showInviteDialog");
-};
-
 // If no party selected, select one.
 Meteor.startup(function () {
   Meteor.autorun(function () {
@@ -24,7 +16,6 @@ Meteor.startup(function () {
 
 ///////////////////////////////////////////////////////////////////////////////
 // Party details sidebar
-///////////////////////////////////////////////////////////////////////////////
 
 Template.details.party = function () {
   return Parties.findOne(Session.get("selected"));
@@ -41,6 +32,44 @@ Template.details.creatorName = function () {
   return displayName(owner);
 };
 
+Template.details.canRemove = function () {
+  return this.owner === Meteor.userId() && attending(this) === 0;
+};
+
+Template.details.maybeChosen = function (what) {
+  var myRsvp = _.find(this.rsvps, function (r) {
+    return r.user === Meteor.userId();
+  }) || {};
+
+  return what == myRsvp.rsvp ? "chosen btn-inverse" : "";
+};
+
+Template.details.events({
+  'click .rsvp_yes': function () {
+    Meteor.call("rsvp", Session.get("selected"), "yes");
+    return false;
+  },
+  'click .rsvp_maybe': function () {
+    Meteor.call("rsvp", Session.get("selected"), "maybe");
+    return false;
+  },
+  'click .rsvp_no': function () {
+    Meteor.call("rsvp", Session.get("selected"), "no");
+    return false;
+  },
+  'click .invite': function () {
+    openInviteDialog();
+    return false;
+  },
+  'click .remove': function () {
+    Parties.remove(this._id);
+    return false;
+  }
+});
+
+///////////////////////////////////////////////////////////////////////////////
+// Party attendance widget
+
 Template.attendance.rsvpName = function () {
   var user = Meteor.users.findOne(this.user);
   return displayName(user);
@@ -48,9 +77,10 @@ Template.attendance.rsvpName = function () {
 
 Template.attendance.outstandingInvitations = function () {
   var party = Parties.findOne(this._id);
-  // take out the people that have already rsvp'd
-  var people = _.difference(party.invited, _.pluck(party.rsvps, 'user'));
-  return Meteor.users.find({_id: {$in: people}});
+  return Meteor.users.find({$and: [
+    {_id: {$in: party.invited}}, // they're invited
+    {_id: {$nin: _.pluck(party.rsvps, 'user')}} // but haven't RSVP'd
+  ]});
 };
 
 Template.attendance.invitationName = function () {
@@ -69,102 +99,49 @@ Template.attendance.canInvite = function () {
   return ! this.public && this.owner === Meteor.userId();
 };
 
-Template.details.canRemove = function () {
-  return this.owner === Meteor.userId() && attending(this) === 0;
-};
-
-Template.details.maybeChosen = function (what) {
-  var myRsvp = _.find(this.rsvps, function (r) {
-    return r.user === Meteor.userId();
-  }) || {};
-
-  return what == myRsvp.rsvp ? "chosen btn-inverse" : "";
-};
-
-// XXX show which button is currently selected
-Template.details.events({
-  // XXX demonstrate error handling?
-  'click .rsvp_yes': function () {
-    Meteor.call("rsvp", Session.get("selected"), "yes");
-    return false;
-  },
-  'click .rsvp_maybe': function () {
-    Meteor.call("rsvp", Session.get("selected"), "maybe");
-    return false;
-  },
-  'click .rsvp_no': function () {
-    Meteor.call("rsvp", Session.get("selected"), "no");
-    return false;
-  },
-  'click .invite': function () {
-    Session.set("showInviteDialog", true);
-    return false;
-  },
-  'click .remove': function () {
-    Parties.remove(this._id);
-    return false;
-  }
-});
-
 ///////////////////////////////////////////////////////////////////////////////
 // Map display
-///////////////////////////////////////////////////////////////////////////////
 
-// XXX fold into package? domutils?
 // http://stackoverflow.com/questions/55677/how-do-i-get-the-coordinates-of-a-mouse-click-on-a-canvas-element
-function relMouseCoords (element, event) {
-  var totalOffsetX = 0;
-  var totalOffsetY = 0;
-  var canvasX = 0;
-  var canvasY = 0;
-  var currentElement = element;
+var coordsRelativeToElement = function (element, event) {
+  var totalOffsetX = 0, totalOffsetY = 0;
 
   do {
-    totalOffsetX += currentElement.offsetLeft - currentElement.scrollLeft;
-    totalOffsetY += currentElement.offsetTop - currentElement.scrollTop;
-  }
-  while (currentElement = currentElement.offsetParent)
+    totalOffsetX += element.offsetLeft - element.scrollLeft;
+    totalOffsetY += element.offsetTop - element.scrollTop;
+  } while (element = element.offsetParent);
 
-  canvasX = event.pageX - totalOffsetX;
-  canvasY = event.pageY - totalOffsetY;
-
-  return {x: canvasX, y: canvasY};
-}
+  return {
+    x: event.pageX - totalOffsetX,
+    y: event.pageY - totalOffsetY
+  };
+};
 
 Template.map.events = {
   'mousedown circle, mousedown text': function (event, template) {
     Session.set("selected", event.currentTarget.id);
   },
   'dblclick svg': function (event, template) {
-    // must be logged in
-    if (!Meteor.userId())
+    if (! Meteor.userId()) // must be logged in to create events
       return;
-    var coords = relMouseCoords(event.currentTarget, event);
-    Session.set("createCoords", {
-      x: coords.x / 500, // XXX event.currentTarget.width?
-      y: coords.y / 500
-    });
-    Session.set("showCreateDialog", true);
+    var coords = coordsRelativeToElement(event.currentTarget, event);
+    openCreateDialog(coords.x / 500, coords.y / 500);
   }
 };
 
 Template.map.rendered = function () {
   var self = this;
-  self.node = this.find("svg");
+  self.node = self.find("svg");
 
   if (! self.handle) {
     self.handle = Meteor.autorun(function () {
       var selected = Session.get('selected');
       var selectedParty = selected && Parties.findOne(selected);
-
       var radius = function (party) {
         return 10 + Math.sqrt(attending(party)) * 10;
       };
 
       // Draw a circle for each party
-      var circles = d3.select(self.node).select(".circles").selectAll("circle")
-        .data(Parties.find().fetch(), function (party) { return party._id; });
-
       var updateCircles = function (group) {
         group.attr("id", function (party) { return party._id; })
         .attr("cx", function (party) { return party.x * 500; })
@@ -178,14 +155,14 @@ Template.map.rendered = function () {
         });
       };
 
-      updateCircles(circles.enter().append("circle"));
-      updateCircles(circles.transition().duration(250).ease("cubic-out"));
-      circles.exit().remove();
-
-      // Label each with the current attendance count
-      var labels = d3.select(self.node).select(".labels").selectAll("text")
+      var circles = d3.select(self.node).select(".circles").selectAll("circle")
         .data(Parties.find().fetch(), function (party) { return party._id; });
 
+      updateCircles(circles.enter().append("circle"));
+      updateCircles(circles.transition().duration(250).ease("cubic-out"));
+      circles.exit().transition().duration(250).attr("r", 0).remove();
+
+      // Label each with the current attendance count
       var updateLabels = function (group) {
         group.attr("id", function (party) { return party._id; })
         .text(function (party) {return attending(party) || '';})
@@ -196,6 +173,9 @@ Template.map.rendered = function () {
         });
       };
 
+      var labels = d3.select(self.node).select(".labels").selectAll("text")
+        .data(Parties.find().fetch(), function (party) { return party._id; });
+
       updateLabels(labels.enter().append("text"));
       updateLabels(labels.transition().duration(250).ease("cubic-out"));
       labels.exit().remove();
@@ -221,16 +201,25 @@ Template.map.destroyed = function () {
 
 ///////////////////////////////////////////////////////////////////////////////
 // Create Party dialog
-///////////////////////////////////////////////////////////////////////////////
+
+var openCreateDialog = function (x, y) {
+  Session.set("createCoords", {x: x, y: y});
+  Session.set("createError", null);
+  Session.set("showCreateDialog", true);
+};
+
+Template.page.showCreateDialog = function () {
+  return Session.get("showCreateDialog");
+};
 
 Template.createDialog.events = {
   'click .save': function (event, template) {
     var title = template.find(".title").value;
     var description = template.find(".description").value;
-    var public = !template.find(".private").checked;
+    var public = ! template.find(".private").checked;
+    var coords = Session.get("createCoords");
 
     if (title.length && description.length) {
-      var coords = Session.get("createCoords");
       Meteor.call('createParty', {
         title: title,
         description: description,
@@ -241,12 +230,13 @@ Template.createDialog.events = {
         if (! error) {
           Session.set("selected", party);
           if (! public && Meteor.users.find().count() > 1)
-            Session.set("showInviteDialog", true);
+            openInviteDialog();
         }
       });
       Session.set("showCreateDialog", false);
     } else {
-      // XXX show validation failure
+      Session.set("createError",
+                  "It needs a title and a description, or why bother?");
     }
   },
 
@@ -255,9 +245,20 @@ Template.createDialog.events = {
   }
 };
 
+Template.createDialog.error = function () {
+  return Session.get("createError");
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 // Invite dialog
-///////////////////////////////////////////////////////////////////////////////
+
+var openInviteDialog = function () {
+  Session.set("showInviteDialog", true);
+};
+
+Template.page.showInviteDialog = function () {
+  return Session.get("showInviteDialog");
+};
 
 Template.inviteDialog.events = {
   'click .invite': function (event, template) {
@@ -272,13 +273,9 @@ Template.inviteDialog.events = {
 Template.inviteDialog.uninvited = function () {
   var party = Parties.findOne(Session.get("selected"));
   if (! party)
-    // XXX this happens on code push when the invite dialog is
-    // open. easy enough to add a guard, but what's the big picture?
-    // do we have to do this everywhere?
-    return [];
-  var invited = _.clone(party.invited);
-  invited.push(party.owner);
-  return Meteor.users.find({_id: {$nin: invited}});
+    return []; // party hasn't loaded yet
+  return Meteor.users.find({$nor: [{_id: {$in: party.invited}},
+                                   {_id: party.owner}]});
 };
 
 Template.inviteDialog.displayName = function () {
diff --git a/examples/parties/client/parties.css b/examples/parties/client/parties.css
index d32fe0efa3..adecec2651 100644
--- a/examples/parties/client/parties.css
+++ b/examples/parties/client/parties.css
@@ -69,4 +69,4 @@ input.chosen {
     stroke-opacity: .8;
     fill: none;
     stroke: red;
-}
\ No newline at end of file
+}
diff --git a/examples/parties/model.js b/examples/parties/model.js
index 7d88b3d4ac..968a990440 100644
--- a/examples/parties/model.js
+++ b/examples/parties/model.js
@@ -1,76 +1,60 @@
+// All Tomorrow's Parties -- data model
+// Loaded on both the client and the server
+
+///////////////////////////////////////////////////////////////////////////////
+// Parties
+
 /*
-  owner: user id
-  x, y: Number (screen coordinates)
-  title, description: String
-  public: Boolean
-  invited: list of user id's that it's shared with, not including
-    the owner (ignored if public)
-  rsvps: XXX document, fields are 'user' and 'rsvp'
+  Each party is represented by a document in the Parties collection:
+    owner: user id
+    x, y: Number (screen coordinates in the interval [0, 1])
+    title, description: String
+    public: Boolean
+    invited: Array of user id's that are invited (only if !public)
+    rsvps: Array of objects like {user: userId, rsvp: "yes"} (or "no"/"maybe")
 */
 Parties = new Meteor.Collection("parties");
 
 Parties.allow({
   insert: function (userId, party) {
-    return false; // use createParty method instead
+    return false; // no cowboy inserts -- use createParty method
   },
   update: function (userId, parties, fields, modifier) {
     return _.all(parties, function (party) {
       if (userId !== party.owner)
         return false; // not the owner
+
       var allowed = ["title", "description", "x", "y"];
       if (_.difference(fields, allowed).length)
         return false; // tried to write to forbidden field
 
-      // XXX validate that they keep the right types, and don't write
-      // stupidly long strings to the database. since all we have is a
-      // modifier that take a little logic.
-
+      // A good improvement would be to validate the type of the new
+      // value of the field (and if a string, the length.) In the
+      // future Meteor will have a schema system to makes that easier.
       return true;
     });
   },
   remove: function (userId, parties) {
     return ! _.any(parties, function (party) {
+      // deny if not the owner, or if other people are going
       return party.owner !== userId || attending(party) > 0;
     });
   }
 });
 
 var attending = function (party) {
-  return _.reduce(party.rsvps, function (memo, rsvp) {
-    if (rsvp.rsvp === 'yes')
-      return memo + 1;
-    else
-      return memo;
-  }, 0);
-};
-
-var displayName = function (user) {
-  if (user.profile && user.profile.name)
-    return user.profile.name;
-  return user.emails[0].address;
-};
-
-var contactEmail = function (user) {
-  if (user.emails && user.emails.length)
-    return user.emails[0].address;
-  if (user.services.facebook && user.services.facebook.email)
-    return user.services.facebook.email;
-  return null;
+  return (_.groupBy(party.rsvps, 'rsvp').yes || []).length;
 };
 
 Meteor.methods({
-  // title, description, x, y, public
-  // XXX limit a user to a certain number of parties
+  // options should include: title, description, x, y, public
   createParty: function (options) {
     options = options || {};
     if (! (typeof options.title === "string" && options.title.length &&
            typeof options.description === "string" &&
            options.description.length &&
-           typeof options.x === "number" &&
-           options.x >= 0 && options.x <= 1 &&
-           typeof options.y === "number" &&
-           options.y >= 0 && options.y <= 1))
-      // XXX should get rid of the error code
+           typeof options.x === "number" && options.x >= 0 && options.x <= 1 &&
+           typeof options.y === "number" && options.y >= 0 && options.y <= 1))
       throw new Meteor.Error(400, "Required parameter missing");
     if (options.title.length > 100)
       throw new Meteor.Error(413, "Title too long");
@@ -104,15 +88,16 @@ Meteor.methods({
       var from = contactEmail(Meteor.users.findOne(this.userId));
       var to = contactEmail(Meteor.users.findOne(userId));
       if (Meteor.isServer && to) {
+        // This code only runs on the server. If you didn't want clients
+        // to be able to see it, you could move it to a separate file.
         Email.send({
           from: "noreply@example.com",
           to: to,
           replyTo: from || undefined,
           subject: "PARTY: " + party.title,
           text:
-"Hey, I just invited you to '" + party.title + "' on All Tomorrow's Parties.\n" +
-"\n" +
-"Come check it out at: " + Meteor.absoluteUrl() + "\n"
+"Hey, I just invited you to '" + party.title + "' on All Tomorrow's Parties." +
+"\n\nCome check it out: " + Meteor.absoluteUrl() + "\n"
         });
       }
     }
@@ -126,8 +111,10 @@ Meteor.methods({
     var party = Parties.findOne(partyId);
     if (! party)
       throw new Meteor.Error(404, "No such party");
-    if (! party.public && party.owner !== this.userId && !_.contains(party.invited, this.userId))
-      throw new Meteor.Error(403, "No such party"); // private, but let's not tell this to the user
+    if (! party.public && party.owner !== this.userId &&
+        !_.contains(party.invited, this.userId))
+      // private, but let's not tell this to the user
+      throw new Meteor.Error(403, "No such party");
 
     var rsvpIndex = _.indexOf(_.pluck(party.rsvps, 'user'), this.userId);
     if (rsvpIndex !== -1) {
@@ -139,18 +126,37 @@ Meteor.methods({
           {_id: partyId, "rsvps.user": this.userId},
           {$set: {"rsvps.$.rsvp": rsvp}});
       } else {
-        // minimongo doesn't yet support $ in modifier. reconstruct
-        // the modifier to be of the form:
-        //   {$set: {"rsvps.<index>.rsvp"}}
+        // minimongo doesn't yet support $ in modifier. as a temporary
+        // workaround, make a modifier that uses an index. this is
+        // safe on the client since there's only one thread.
         var modifier = {$set: {}};
         modifier.$set["rsvps." + rsvpIndex + ".rsvp"] = rsvp;
         Parties.update(partyId, modifier);
       }
+
+      // Possible improvement: send email to the other people that are
+      // coming to the party.
     } else {
       // add new rsvp entry
-      Parties.update(
-        partyId,
-        {$push: {rsvps: {user: this.userId, rsvp: rsvp}}});
+      Parties.update(partyId,
+                     {$push: {rsvps: {user: this.userId, rsvp: rsvp}}});
     }
   }
 });
+
+///////////////////////////////////////////////////////////////////////////////
+// Users
+
+var displayName = function (user) {
+  if (user.profile && user.profile.name)
+    return user.profile.name;
+  return user.emails[0].address;
+};
+
+var contactEmail = function (user) {
+  if (user.emails && user.emails.length)
+    return user.emails[0].address;
+  if (user.services && user.services.facebook && user.services.facebook.email)
+    return user.services.facebook.email;
+  return null;
+};
diff --git a/examples/parties/parties.html b/examples/parties/parties.html
index 69ecd312fa..9d68cb371d 100644
--- a/examples/parties/parties.html
+++ b/examples/parties/parties.html
@@ -8,7 +8,6 @@
 </body>
 
 <template name="page">
-
   {{#if showCreateDialog}}
     {{> createDialog}}
   {{/if}}
@@ -17,99 +16,38 @@
     {{> inviteDialog}}
   {{/if}}
 
-
   <div class="container">
     <div class="row">
       <div class="span1"> </div>
+
       <div class="span10">
-
-    <div class="header row">
-      <div class="span5">
-        <h3 style="margin-bottom: 0px">All Tomorrow's Parties</h3>
-      </div>
-      <div class="span5">
-        <div style="float: right">
-          {{loginButtons align="right"}}
-        </div>
-      </div>
-    </div>
-
-    <div class="row">
-      <div class="span6">
-        {{> map}}
-        {{#if currentUser}}
-          <div class="pagination-centered">
-            <em><small>Double click the map to post a party!</small></em>
+        <div class="header row">
+          <div class="span5">
+            <h3 style="margin-bottom: 0px">All Tomorrow's Parties</h3>
+          </div>
+          <div class="span5">
+            <div style="float: right">
+              {{loginButtons align="right"}}
+            </div>
           </div>
-        {{/if}}
-      </div>
-      <div class="span4">
-        {{> details}}
-      </div>
-    </div>
-
-
-      </div>
-      <div class="span1"> </div>
-    </div>
-
-
-  </div>
-</template>
-
-<template name="createDialog">
-  <div class="mask"> </div>
-  <div class="modal">
-    <div class="modal-header">
-      <button type="button" class="close cancel">&times;</button>
-      <h3>Add party</h3>
-    </div>
-
-    <div class="modal-body">
-
-      <label>Title</label>
-      <input type="text" class="title span5">
-
-      <label>Description</label>
-
-      <textarea class="description span5"></textarea>
-
-      <label class="checkbox">
-        <input type="checkbox" class="private">
-        Private party &mdash; invitees only
-      </label>
-
-    </div>
-
- <div class="modal-footer">
-    <a href="#" class="btn cancel">Cancel</a>
-    <a href="#" class="btn btn-primary save">Add party</a>
-  </div>
-</div>
-  </div>
-</template>
-
-<template name="inviteDialog">
-  <div class="mask"> </div>
-  <div class="modal">
-    <div class="modal-header">
-      <button type="button" class="close done">&times;</button>
-      <h3>Invite people</h3>
-    </div>
-
-    <div class="modal-body">
-      {{#each uninvited}}
-        <div class="invite-row">
-          <a href="#" class="btn invite">Invite</a>
-          {{displayName}}
         </div>
-      {{else}}
-        Everyone on the site has already been invited.
-      {{/each}}
-    </div>
 
-    <div class="modal-footer">
-      <a href="#" class="btn btn-primary done">Done</a>
+        <div class="row">
+          <div class="span6">
+            {{> map}}
+            {{#if currentUser}}
+            <div class="pagination-centered">
+              <em><small>Double click the map to post a party!</small></em>
+            </div>
+            {{/if}}
+          </div>
+          <div class="span4">
+            {{> details}}
+          </div>
+        </div>
+      </div>
+
+      <div class="span1"> </div>
     </div>
   </div>
 </template>
@@ -117,7 +55,7 @@
 <template name="map">
   <div class="map">
     {{#constant}}
-      <svg width="480" height="480">
+      <svg width="500" height="500">
         <circle class="callout" cx=-100 cy=-100></circle>
         <g class="circles"></g>
         <g class="labels"></g>
@@ -157,8 +95,6 @@
               <b><a href="#" class="remove">delete this listing</a></b>.
           </small></div>
         {{/if}}
-
-
       {{/with}}
     {{else}}
       <h1 class="muted pagination-centered">
@@ -172,7 +108,6 @@
   </div>
 </template>
 
-
 <template name="attendance">
   <div class="attendance well well-small">
     <div class="muted who"><b>Who</b></div>
@@ -216,6 +151,63 @@
         <a href="#" class="btn btn-mini invite">Invite people</a>
       </div>
     {{/if}}
-
   </div>
 </template>
+
+<template name="createDialog">
+  <div class="mask"> </div>
+  <div class="modal">
+    <div class="modal-header">
+      <button type="button" class="close cancel">&times;</button>
+      <h3>Add party</h3>
+    </div>
+
+    <div class="modal-body">
+      {{#if error}}
+        <div class="alert alert-error">{{error}}</div>
+      {{/if}}
+
+      <label>Title</label>
+      <input type="text" class="title span5">
+
+      <label>Description</label>
+      <textarea class="description span5"></textarea>
+
+      <label class="checkbox">
+        <input type="checkbox" class="private">
+        Private party &mdash; invitees only
+      </label>
+    </div>
+
+    <div class="modal-footer">
+      <a href="#" class="btn cancel">Cancel</a>
+      <a href="#" class="btn btn-primary save">Add party</a>
+    </div>
+  </div>
+</template>
+
+<template name="inviteDialog">
+  <div class="mask"> </div>
+  <div class="modal">
+    <div class="modal-header">
+      <button type="button" class="close done">&times;</button>
+      <h3>Invite people</h3>
+    </div>
+
+    <div class="modal-body">
+      {{#each uninvited}}
+        <div class="invite-row">
+          <a href="#" class="btn invite">Invite</a>
+          {{displayName}}
+        </div>
+      {{else}}
+        Everyone on the site has already been invited.
+      {{/each}}
+    </div>
+
+    <div class="modal-footer">
+      <a href="#" class="btn btn-primary done">Done</a>
+    </div>
+  </div>
+</template>
+
diff --git a/examples/parties/server/server.js b/examples/parties/server/server.js
index 6c61f68b78..46ac47b686 100644
--- a/examples/parties/server/server.js
+++ b/examples/parties/server/server.js
@@ -1,4 +1,4 @@
-// XXX autopublish warning is printed on each restart. super spammy!
+// All Tomorrow's Parties -- server
 
 Meteor.publish("directory", function () {
   return Meteor.users.find({}, {fields: {emails: 1, profile: 1}});