Now we're getting somewhere... the future is here and it's hacked out of a wiiremote and some reflective tape.
While writing my Silverlight wish list I found a very nice project. Johnny Ching Lee is using the controller (Wiimote) of the Nintendo Wii to track fingers. The controller does not need the Nintendo Wii console, simple the controller and a bluetooth connection is enough. Combining this project with WPF or Silverlight would be the answer of one of my wishes. (Well, I know what I will try during the holidays.)