Folding@home - Stanford has a thing going that uses the gpu to do science. They used to be part of a larger network of software projects called BOINC. They're trying to get Microsoft to let the xbox do some work also, but it hasn't got off the ground yet. Remember the old Seti@Home stuff? This is what it's evolved into.
BOINC - Berkeley Open Infrastructure for Network Computing.
A grid computer project where your machine can be used to do science problems, you get to pick where the science is used. There are LOTS of different projects to choose from, no longer including Folding@Home - a protein modeling system. Scientists figure out what questions they need answered, submit them as a BOINC project, and people throughout the world use spare CPU time to crank out the answers.
As your computer finishes working a problem, it is assigned 'credit' showing that your not a totally worthless individual, but have some altruistic motives. You can keep these credits to yourself, or join a team of other like minded people.
TomsHardware has a team, here's the link to the forum.
http://forumz.tomshardware.com/community/modules.php?name=Forums&file=viewtopic&t=5081&highlight=boinc
I'd be on Tom's team myself, but I had already signed up for another team, boincsynergy. Here's my stats:
http://www.boincsynergy.com/images/stats/comb-3241.jpg