Some of you may have never heard of this and are wondering what joining the grid even does. Well, for example, I just got an email today saying the Computing for Clean Water project has completed, and the word is the team got some great data and are getting ready to publish their findings soon. That data came from computers on the grid using their combined processing power to tackle the computational aspects of the research.
Unfortunately, I just have my one laptop, and an old one at that. I don't have any extra computers sitting idle for long periods of time, but plenty of people do. When I went to Marist, they'd set up whole computer labs with WCG clients so they'd be churning out results whenever students weren't using them. It's a pretty great idea.
So yeah, if you care about science and helping out good causes like finding new treatment options for AIDS and cancer, and you like the idea of not having to actually do anything to make a difference, installing a grid client on a machine you own and letting it run in the background or as a screensaver is a great idea.