HTTP Cats
this reminds me of <a href="http://placekitten.com" rel="nofollow">http://placekitten.com</a>, the most useful URL for placeholder images ever: placekitten.com/<width>/<height> (e.g. <a href="http://placekitten.com/640/480" rel="nofollow">http://placekitten.com/640/480</a>).