Remember the glory days of the scientific calculator wristwatch? Dave Jones does: "Back in 1987 or so I got a Casio CFX-400 scientific calculator watch, and I wore that watch to death for 10 years until the band support on the case broke. The CFX-400 was the best, and last scientific calculator watch ever sold."
If you're on the same page with Jones, then you'll be happy to hear he's turned reviving the scientific calculator wristwatch into a do-it-yourself project. His uWatch has a roomy LCD able to display 16 characters across, two lines deep, and it can handle all your fancy RPN/Algebraic scientific needs. It'll take a little technical know-how to bring it together, but what you're left with is a geek chic wristwatch that'll catch the eye of many a pocket protector-wearing lass.