Anybody ever seen the movie, Minority Report? Well, you remember the computer screens they had, where they had no mouse, no keyboard, and the screen was manipulated by just waving your hands in the air? I think there have been a few anime, too, with the same idea.
Anyway, the technology is pretty much feasible now.
Microsoft is coming out with a similar device for the Xbox videogame system, currently called "project Natal":
http://www.engadget.com/2009/06/01/micr ... -xbox-360/
On that page, there's a neat video of somebody manipulating a game just by waving their hands in the air. Microsoft already developed state-of-the-art touch-screen technology a while ago, that lets you do the same thing by touching a screen... But this new technology uses motion-capture video and spatial recognition software to identify the positions of a person's body, and even identify their face (they're saying that with this peripheral, the game could automatically log you on by just seeing your face).
Some other videos of this sort of thing:
Just a few... There's a whole bunch of companies and groups making this technology, so it'll probably be standard in liek 5 to 10 years.