Picked up this project from Custom PC magazine... seems a really good idea. The site can explain it alot better than me:
What does Folding@Home do? Folding@Home is a distributed computing project which studies protein folding, misfolding, aggregation, and related diseases. We use novel computational methods and large scale distributed computing, to simulate timescales thousands to millions of times longer than previously achieved. This has allowed us to simulate folding for the first time, and to now direct our approach to examine folding related disease.
All that ^^ means that you download the core program, leave it running with your CPU crunching numbers and you contribute to science! We can even make a CDFreaks team to show how many points people have contributed.
Start here: http://folding.stanford.edu/