Folding@Home
Folding@home (F@H) is a distributed computing project run by Stanford Univesity. It uses your spare processor time to simulate protein folding. Work is farmed out to your PC, which does lots of number crunching and sends the results back to Stanford, where they use the data to help understand, mitigate and cure all manner of diseases. It's similar to SETI@home, but with more immediately useful results.
To give people a sense of acheivement, and to see how they're helping, each user is scored by their contributions to the project. Each user can also join teams, and cumulative points are then awarded.
You can find out much more about the project at its website.
The Nottingham Hackspace team number is 208902. If you want to join, download the appropriate application for you computer here. At some stage you will be asked for your team number. Enter 208902, and you'll be scoring points for Nottinghack!