Small snippet for Ghost, load asset first from a CDN to minimize the server requests or load from our local source if it's unavailable (we take advantage of Handlebars path expressions):

<script type='text/javascript' src='//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js'></script>
<script>window.jQuery || document.write('<script src="{{asset "js/jquery.min.js"}}"><\/script>')</script>

Remember: YOU own your availability