Keef, it's a headphone amplifier. I've built two. The first was a failure (pretty sure I posted it in the electronics section), and the second one I gave away. Go here for more info:
http://tangentsoft.net/audio/cmoy-tutorial/
Anyway, which were the life-savers that spark when you bite them? I think it was the wintergreen ones. When they crack in half, they discharge a small amount of electricity... I think I saw that on mythbusters.
