Found it!
http://www.cdnjs.com/libraries/prettify
<script src="http://cdnjs.cloudflare.com/ajax/libs/prettify/r298/run_prettify.js" type="text/javascript"></script>
<link href="http://cdnjs.cloudflare.com/ajax/libs/prettify/r298/prettify.css" type="text/css">
Update: https://github.com/cdnjs/cdnjs/issues/695 (see bottom of page)