Skinput Transforms Human Body Into Touch Input Device (via PCWorld)
A research partnership between Carnegie Mellon University and Microsoft has produced a novel method of physical interaction targeted at mobile devices that uses skin as an input interface. This input method, known as “Skinput,” measures the generated by tapping on your body.
This sounds weird, but watching the video, the solutions looks very sound. Especially with the pico-projector projecting a user interface on the arm.