I do a lot of numerical computing, and whenever my machine has nothing to solve, I give the idle CPU time to SETI@home.
Thoughts about SETI and SETI@home
I run SETI@home because I think it is a worthwile cause. I think is is a great project and I'm very impressed by the size of computational power available to the SETI@home team.
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.