Have a look at the University of Tokyo research http://www.k2.t.u-tokyo.ac.jp/fusion/LaserActiveTracking/ .

"The whole PDA could fit in a keyboardless, screenless chest pin, that when activated will follow hand gestures, and write back information on the palm of the same hand " , doesn't this remind you of star trek?

Think of using this for activities like tele-surgery , remote controlled vehicles etc.,