Gladly, I'll just copy and paste the intro from their main site:
Risus is a complete Role Playing Game (RPG) designed to provide an "RPG Lite" for those nights when the brain is too tired for exacting detail. Risus is especially valuable to GMs assembling a quick convention game, or any late-night beer-and-pretzels outing. While it is essentially a Universal Comedy System, it works just as well for serious play (if you insist!). Best of all, a Risus character takes about 20 seconds to create!
Risus: The Anything RPG (A Free RPG from S. John Ross, he's written some GURPS books, I don't recall which ones.)
http://www222.pair.com/sjohn/risus.htm
Anyway, if you go to the site you can download the rules in PDF TXT or Word. Really simple, plus the rules book is really funny; gatta love all the stick figures.