Foldit is a web-based computer game that lets you fold proteins, and contribute to science while playing.
From the site:
“Figuring out which of the many, many possible structures is the best one is regarded as one of the hardest problems in biology today and current methods take a lot of money and time, even for computers. Foldit attempts to predict the structure of a protein by taking advantage of humans’ puzzle-solving intuituions and having people play competitively to fold the best proteins.”
It’s similar to Folding @ Home, in that it solves the same problems, but this needs your interaction and Folding @ Home mainly wants your computing power.