More altruistic uses of the PS3...

http://news.bbc.co.uk/1/hi/technology/7074547.stm

Sony wanted an altruistic program to try to demonstrate the computing power of their cell technology and they chose folding@home. Not a cool game or anything but I'm more than happy to help out when I'm not playing a game or watching a movie. I've been folding since June/July and nothing adverse to report at this time.

The article explains the distributive computing network and what folding@home does better than I could.