FightAIDS@home

Like its name says, this project tries to find a cure for AIDS. It is being developed by Olson Laboratory. They try to find the right molecules (shape + interaction specifics) that could fight the AIDS molecule.

One catch though: this is a for-profit organization and will run commercial project on your computer once in a while, it is less than 5% according to their stats.

http://www.fightaidsathome.org/
Software is for Windows