Boing Boing: Implanting a magnet in your fingertip adds a sixth sense:
This morning's Wired News has a fascinating article on the practice of implanting small, strong rare-earth magnets in one's ring-finger. The result is a kind of "magnet sense" -- people who've had the implant report that they can tell when a wire is live and when they're going through a magnet security-scanner at a store, even when their laptops' hard drives are spinning up.
Quinn Norton of Wired News has had the operation and writes in detail about how it felt, what the problems were, and what she was able to do once it was in place. The most amazing part is that months after the magnet implant fragmented and Quinn lost her "sixth sense," it reassembled itself (magnets tend to draw towards one another) and the sense returned.