An odd question

I find myself with a dual 2 ghz, 512 mb of ram, ATA 100, 50 gigs HD, etc. I am running Windows 2000 professional. Now, I feel like I am wasting this power on games. I was curious as to there was any effective way to utilize my processing power. I understand Seti was doing an odd sort of screen saver in which you processed data for them and sent it back, are there any other such groups?

What about programs, I would like to see what this thing can really do.