An easy to install easter-egg for any website inspired by a Boing Boing post -> http://www.boingboing.net/2010/05/26/keyboard-shortcuts.html
Visit http://jmhobbs.github.com/Konami-Unicorn-Blitz
KUB is MIT licensed, so you can do pretty much whatever you would like with them.
The unicorn images are from a now defunct url, http://www.webfetti.com/MySpace/Glitter/Animals.jhtml
They were listed as free to use, but you will need to make your own decision if you want to use them.