I don't link to a lot of YouTube clips, but this one has to be seen to be drooled over. Demonstrated is a multi-touch light table setup, a two-dimensional version of the interface seen in Minority Report. You use your hands to manipulate images. It's fully intuitive, seamless, and magical to behold--and if its spokesman, Jeff Han, is right, will "change the way we interact with machines."
Hat tip: my 5th period techno-geeks.