Sample RequireJS setup with some light failover for CSS.

config.js

/*global requirejs, define, require, CI, $, jQuery */
/*jslint devel: true, browser: true */
/**
 * Require Config
 * This is all the core scripts needed to be available at runtime.
 * Includes CDN and local file fail over.
 * Shim will control the availability of dependent libraries/scripts.
 * domReady included to insure it all kicks off right.
 * @usage <script data-main="js/config" src="js/vendor/requirejs/require.min.js"></script>
 */
requirejs.config({
    urlArgs: "ts=" + new Date().getTime(), // disable caching - remove in production
    paths: {
        // Rack up CDN and local fail over files - '.js' not needed.
        domReady: [
            "//cdnjs.cloudflare.com/ajax/libs/require-domReady/2.0.1/domReady.min",
            "vendor/requirejs/plugins/domReady.min"
        ],
        modernizr: [
            "//cdnjs.cloudflare.com/ajax/libs/modernizr/2.8.3/modernizr.min",
            "vendor/modernizr.min"
        ],
        prefixfree: [
            "//cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min",
            "vendor/prefixfree.min"
        ],
        jquery: [
            "//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min",
            "vendor/jquery/2.1.1/jquery.min"
        ],
        bootstrap: [
            "//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.1/js/bootstrap.min",
            "vendor/twitter-bootstrap/3.3.1/bootstrap.min"
        ],
        // GSAP
        tweenmax: [
            "//cdnjs.cloudflare.com/ajax/libs/gsap/1.15.0/TweenMax.min",
            "vendor/gsap/1.15.0/TweenMax.min"
        ],
        kineticplugin: [
            "//cdnjs.cloudflare.com/ajax/libs/gsap/1.15.0/plugins/KineticPlugin.min",
            "vendor/gsap/1.15.0/plugins/KineticPlugin.min"
        ],
        throwpropsplugin: [ // licensed plugin
            "vendor/gsap/1.15.0/plugins/ThrowPropsPlugin.min"
        ],
        draggable: [
            "//cdnjs.cloudflare.com/ajax/libs/gsap/1.15.0/utils/Draggable.min",
            "vendor/gsap/1.15.0/utils/Draggable.min"
        ],
        jquerygsap: [
            "//cdnjs.cloudflare.com/ajax/libs/gsap/1.15.0/jquery.gsap.min",
            "vendor/gsap/1.15.0/jquery.gsap.min"
        ],
        // Local
        trace: [
            "vendor/jquery/plugins/trace"
        ],
        site: [
            "site/Site"
        ],
        email: [
            "site/email/Email"
        ]
        // End
    },
    shim: {
        // defined dependencies on scripts
        'domReady'         : ['site'],
        'bootstrap'        : ['jquery'],
        'trace'            : ['jquery'],
        'tweenmax'         : ['jquery'],
        'kineticplugin'    : ['tweenmax'],
        'throwpropsplugin' : ['tweenmax'],
        'draggable'        : ['tweenmax'],
        'jquerygsap'       : ['tweenmax'],
        'site'             : ['bootstrap'],
        'email'            : ['site']
    }
});
/*
 * Tip:
 * 'define' appears to be a module/JS you depend on
 * 'require' just loads most likely async and you can't rely on domReady then.
 * Other examples online show domReady, and $ being passed in as arguments.  I was unsuccessful getting that to work
 * but '$' appears to be accessible when 'define' used.
 */
define([
    'domReady',
    'modernizr',
    'prefixfree',
    'jquery',
    'bootstrap',
    'trace',
    'tweenmax',
    'kineticplugin',
    'throwpropsplugin',
    'draggable',
    'jquerygsap',
    'site',
    'email'], function (domReady) {
    "use strict";
    // Ready, Set, Go...
    domReady(function () {
        // Verify CSS - not a huge fan of this.
        var ss  = document.styleSheets,
            len = ss.length,
            i   = 0,
            sheet,
            rules,
            isError;
        while (i < len) {
            sheet = ss[i];
            rules = sheet.rules ? sheet.rules : sheet.cssRules;
            isError = rules.length === 0;
            if (sheet.href !== null) {
                // Bootstrap
                if (sheet.href.toString().indexOf('twitter-bootstrap') > 0 && isError) {
                    $('<link rel="stylesheet" type="text/css" href="css/bootstrap/3.3.1/css/bootstrap.min.css" />').appendTo('head');
                }
                // Font Awesome
                if (sheet.href.toString().indexOf('font-awesome') > 0 && isError) {
                    $('<link rel="stylesheet" type="text/css" href="css/font-awesome/4.2.0/css/font-awesome.min.css" />').appendTo('head');
                }
            }
            i += 1;
        }
        // Fire up App
        CI.init();
    });
});