diff --git a/docs/client/concepts.html b/docs/client/concepts.html
index cd26c5ef26..49c02bcfed 100644
--- a/docs/client/concepts.html
+++ b/docs/client/concepts.html
@@ -43,6 +43,12 @@ client.  It minifies this bundle and serves it to each new client.
 You're free to use a single JavaScript file for your entire application, or
 create a nested tree of separate files, or anything in between.
 
+Some JavaScript libraries only work when placed in the
+`client/compatibility` subdirectory.  Files in this directory are
+executed without being wrapped in a new variable scope.  This means
+that each top-level `var` defines a global variable. In addition,
+these files are executed before other client-side JavaScript files.
+
 Files outside the `client`, `server` and `tests` subdirectories are loaded on
 both the client and the server!  That's the place for model definitions and
 other functions.  Meteor provides the variables [`isClient`](#meteor_isclient) and
diff --git a/packages/meteor/package.js b/packages/meteor/package.js
index dafe07c090..01946c1b9d 100644
--- a/packages/meteor/package.js
+++ b/packages/meteor/package.js
@@ -6,12 +6,13 @@ Package.describe({
 });
 
 Package.register_extension(
-  "js", function (bundle, source_path, serve_path, where) {
+  "js", function (bundle, source_path, serve_path, where, opt) {
     bundle.add_resource({
       type: "js",
       path: serve_path,
       source_file: source_path,
-      where: where
+      where: where,
+      compatibility: opt.compatibility
     });
   }
 );
diff --git a/tools/bundler.js b/tools/bundler.js
index 5dbab04c24..c0f51ab055 100644
--- a/tools/bundler.js
+++ b/tools/bundler.js
@@ -115,7 +115,7 @@ var PackageBundlingInfo = function (pkg, bundle) {
       });
     },
 
-    add_files: function (paths, where) {
+    add_files: function (paths, where, opt) {
       if (!(paths instanceof Array))
         paths = paths ? [paths] : [];
       if (!(where instanceof Array))
@@ -123,7 +123,7 @@ var PackageBundlingInfo = function (pkg, bundle) {
 
       _.each(where, function (w) {
         _.each(paths, function (rel_path) {
-          self.add_file(rel_path, w);
+          self.add_file(rel_path, w, opt);
         });
       });
     },
@@ -188,8 +188,11 @@ _.extend(PackageBundlingInfo.prototype, {
     return candidates[0];
   },
 
-  add_file: function (rel_path, where) {
+  // opt {Object}
+  //   - compatibility {Boolean} In case this is a JS file, don't wrap in a closure.
+  add_file: function (rel_path, where, opt) {
     var self = this;
+    opt = opt || {};
 
     if (self.files[where][rel_path])
       return;
@@ -210,7 +213,8 @@ _.extend(PackageBundlingInfo.prototype, {
       handler(self.bundle.api,
               sourcePath,
               path.join(self.pkg.serve_root, rel_path),
-              where);
+              where,
+              opt);
     } else {
       // If we don't have an extension handler, serve this file
       // as a static resource.
@@ -302,6 +306,10 @@ var Bundle = function () {
      *
      * data: the data to send. overrides source_file if present. you
      * must still set path (except for "head" and "body".)
+     *
+     * compatibility: (only for js files) when set, don't wrap code in
+     * a closure.  used for client-side javascript libraries that use
+     * the `function foo()` or `var foo =` syntax to define globals.
      */
     add_resource: function (options) {
       var source_file = options.source_file || options.path;
@@ -337,11 +345,16 @@ var Bundle = function () {
             // scope (eg, file-level vars are file-scoped). On the server, this
             // is done in server/server.js to inject the Npm symbol.
             //
+            // Some client-side Javascript libraries define globals with `var foo =` or
+            // `function bar()` which only work if loaded directly from a script tag. If
+            // `options.compatibility` is set, don't wrap in a closure to enable using
+            // such libraries.
+            //
             // The ".call(this)" allows you to do a top-level "this.foo = "
             // to define global variables when using "use strict"
             // (http://es5.github.io/#x15.3.4.4); this is the only way to do
             // it in CoffeeScript.
-            if (w === "client") {
+            if (w === "client" && !options.compatibility) {
               wrapped = Buffer.concat([
                 new Buffer("(function(){ "),
                 data,
@@ -673,7 +686,7 @@ _.extend(Bundle.prototype, {
         contents = self.files.client[file];
         delete self.files.client[file];
         self.files.client_cacheable[file] = contents;
-        url = file + '?' + sha1(contents)
+        url = file + '?' + sha1(contents);
       }
       else
         throw new Error('unable to find file: ' + file);
diff --git a/tools/packages.js b/tools/packages.js
index 8e98150976..4930b52f0f 100644
--- a/tools/packages.js
+++ b/tools/packages.js
@@ -238,7 +238,13 @@ _.extend(Package.prototype, {
       api.use(project.get_packages(app_dir));
 
       // -- Source files --
-      api.add_files(sources_except(api, "server"), "client");
+      var inCompatibilityMode = function (filename) {
+        return filename.indexOf(path.sep + 'client' + path.sep + 'compatibility' + path.sep) !== -1;
+      };
+      var clientFiles = sources_except(api, "server");
+      api.add_files(_.filter(clientFiles, inCompatibilityMode), "client", {compatibility: true});
+      api.add_files(_.reject(clientFiles, inCompatibilityMode), "client");
+
       api.add_files(sources_except(api, "client"), "server");
     });