This is a demonstration I gave of a physical, gesture based interface in 2003. This system was designed and built using very cheap, off the shelf electronics and some basic software - we were pretty happy with the results: the ability to manipulate the playback of a piece of video using the motion of our hands.
In this video we lay out the core idea of the project, explain our objectives, and outline the approach we took to solve the various challenges.
The other handsome devil in this video is Kevin Cannon, currently blazing a trail at CIID (ciid.dk/) Copenhagen.