CDNs fail, but your scripts don’t have to – fallback from CDN to local jQuery:

Even better, RequireJS has a really cool shorthand for fallback URLs which makes me smile:

requirejs.config({
    enforceDefine: true,
    paths: {
        jquery: [
            '//ajax.aspnetcdn.com/ajax/jquery/jquery-2.0.0.min',
            //If the CDN location fails, load from this location
            'js/jquery-2.0.0.min'
        ]
    }
});
//Later
require(['jquery'], function ($) {
});

With RequireJS you can then setup dependencies between modules as well and it will take care of the details.

Good insight on potential CDN problems, and great mitigation plan.