Stanford University is operating the "Folding@Home" distributed computing system to try to develop a better understanding of how proteins fold, or misfold. This may sound extremely esoteric, but as their disease FAQ points-out, this understanding is relevant to Alzheimer's, Huntington's, cancers associated with malfunctions of the p53 protein, Osteogenesis imperfecta, and the development of antibiotics.
The existence of this project is old news to a lot of us—it's been going on since 2001 at least—but it stands to reason that most of the Internet community is still unaware of it, so I wanted to give it a plug in case it happens to be news to anyone reading this. Having lost one friend to cancer this year, and watching another one fighting it, the cancer-related work of this project has acquired new meaning for me.
Anyone with a Macintosh, Linux, or Windows machine can download and run the Folding@Home software, as can owners of PlayStation 3 game consoles, and begin contributing your computer's spare time to shed light on the aforementioned diseases, and many other problems.
As a technological aside, here's hoping that they produce a client that will use the OpenCL technology in Apple's forthcoming Snow Leopard operating system (Mac OS X 10.6) to harness the power of the GPUs in Macintoshes (something that the project has thus far neglected, as, indeed, they neglected to ever take advantage of the multi-CPU PowerPC Macs).