Great Videos: Jeff Han's Multi-touch Sensing Display
Jeff Han is a research scientist for New York University's Courant Institute of Mathematical Sciences. Over the past few years, he has been focusing on developing technology for "multi-touch sensing" and has come up with the a radical new user interface, the multi-touch display.
A demo of this interface is shown here. This video is already extremely popular, so you may already have seen this. If you have not, I highly recommend it - this is truly the future of User Interface.
Here is another video that demonstrates the Microsoft touchscreen coffee table, based on the same technology.