BOINC

This what I get sitting for hours next to a client who is a rocket scientist...literally. Well he launches stuff that's like 2 steps above model rockets. Things that break the sound barrier and launch themselves 10,000 ft into the air.

Anyway, if you can't decide between looking for alien life (SETI) or folding proteins, you can use the BOINC client and now use your non-used personal computing power for a number of cumulative processing power projects.

The basic idea of all these projects was to use all that idle processing time that computers have when they go to sleep or you're away from your desk. SETI was one of the first, and used the combined computing power to look for signs of life in radio signals collected from space over the years. Folding was a great project from Stanford where your screen saver was a picture of a protein folding. The way proteins fold can create enzymes or cause disease, so learning how and why proteins fold in certain ways could be used to find a cure for various diseases.