World Community Grid is an initiative backed by IBM and others to create a massive “computer grid” for select projects that benefit mankind in a variety of ways. Your role? Allow the time your computer’s unused time to make small computations and send it back to a central server. It doesn’t impact your computer performance and there is a “task box” that shows you precisely how your machine is being used. The projects worked on are defined – Cancer, Aids, Muscular Dystrophy, and SmallPox. Check it out.