The Null Device
In the middle ages, it was the done thing to possess mementi mori, artefacts to remind oneself that life is fleeting and death is inevitable. In 1991, a gentleman by the name of David Kendrick took out a patent on a modern-day equivalent, a wristwatch that displays the (estimated) time one has left to live.
It may not surprise anyone to know that this was mentioned on Proceedings of the Athanasius Kircher Society, a veritable wunderkammer of the outré.
(via Boing Boing)