Touch-Screen with No Screen

I caught this quote from an article over at the BBC:

The other product is from Light Blue Optics, another Cambridge based firm which is showing off a mini projector which turns any surface into a touch sensitive screen.

I played with it for a while, watching then pausing a movie, moving photos around much as you would on Microsoft's Surface computer, and playing a game by simply tapping on the table.

How awesome does that sound? Engadget has a great video demonstration of the device.