At Sun back in the day our workstations tended to have fairly promiscuous login settings, so one of my coworkers took the liberty to launch folding@home on every machine in the org. Listing running processes one day, I saw this thing pegging my CPU; asked around and others had it too. A virus!?! Then he fessed up. Kinda miffed at first but ultimately really cool, so we let the thing keep running. That was my introduction to the whole protein folding problem, and it's really great to see this milestone!