My home computer has lots of spare cycles, overnight or while I am at work. It's fun to participate in SETI@home and I've tried Stanford's Folding@home too. They are certainly better than flying toasters. But I have a serious question. I would like to know which distributing computing projects (in my case, for Mac OS X) have the most potential to make a useful difference in the world. Maybe Berkeley's signal analysis will find E.T., who will tell us how to prevent war or repair the ozone layer. Maybe Stanford's protein research (Folding@home and Genome@home) will lead to a cure for cancer. The purpose of FightAIDSatHome is self explanatory. And maybe there's some reason to care that distributed.net's search for an optimal golomb ruler might lead to advances in X-ray crystallography. There are lists of distributed computing projects such as the Yahoo Home > Science > Computer Science > Distributed Computing > Projects page. Where are other such lists? Does anyone review these projects or make relative judgments about them? Who has advice or opinions on how to decide which projects have the most merit?