I saw 'Contact' on TV the other day and it got me curious about how those astronomers over at SETI are doing these days. One of the first hits on the internet is a link to a project called SETI@home. It is an interesting idea, SETI has acquired a MASSIVE amount of data over the years (and they are still collecting it). It will take them some time for them to comb through all their data on their own, so they've joined a program that allows individuals to 'donate' their idle computer time to running tedious calculations. The result is that SETI now has a computer that can process >500 TeraFLOPS (faster than most of the world's computers).
The group that set up this operates out of Berkeley and is called BOINC for short (Berkeley Open Infrastructure for Network Computing). SETI is only one of a list of potential projects that take advantage of grid computing. You can help model protein folding, the N Queens problem (for the math and chess lovers of the world), or even the universe. Now that I think about it, I remember Eric donating his laptop's idle time to modeling climate change.