After a minute and a half of inactivity, BOINC runs data from one of the four projects I've selected. From their websites:
Climateprediction.net runs climate models to forecast changes in climate
SETI@home is a scientific experiment that uses Internet-connected computers in the Search for Extraterrestrial Intelligence (SETI). You can participate by running a free program that downloads and analyzes radio telescope data.
The malariacontrol.net project is an application that makes use of network computing for stochastic modelling of the clinical epidemiology and natural history of Plasmodium falciparum malaria.
Rosetta@home needs your help to determine the 3-dimensional shapes of proteins in research that may ultimately lead to finding cures for some major human diseases. By running the Rosetta program on your computer while you don't need it you will help us speed up and extend our research in ways we couldn't possibly attempt without your help. You will also be helping our efforts at designing new proteins to fight diseases such as HIV, Malaria, Cancer, and Alzheimer's.
There are so many other projects involving quantum physics, astronomy, medical research, ecosystem studies, and mathematics. I'd love to add them all but I'd never be able to get the assignments back on time. This is a great way to use electricity and computing power that would otherwise be wasted to benefit society. It makes me a little warm and fuzzy.