http://moofx.mad4milk.net/
This link is now broken.
about:
moo.fx is a superlightweight, ultratiny, megasmall javascript effects library, written with prototype.js. moo.fx is not a replacement for script.aculo.us or other effects libraries. It's just a little alternative for people that do not need more than just simple, basic effects (and want to keep their filesize small).
