Need a supercomputer to do millions of calculations? Don't care if it has very little RAM? 16 PS3s were used to create the PS3 Gravity Grid, which has been studying how black holes vibrate.
http://www.space.com/businesstechnology/090128-playstation3-blackholes.html
http://www.space.com/businesstechnology/090128-playstation3-blackholes.html