This guy seems to work on some really cool stuff!

The Multi-Touch Interaction Research video has been circulating a lot recently, but if you haven't seen it yet, do have a look.

Less widely circulating is the LED Touch Display movie, which demonstrates a neat mutli-touch-capable input device implemented solely using LEDs (as input devices, mind you!) Didn't know LEDs could be used as photodiodes? Well, neither did I...

Finally, Holodust is a fascinating true open-air 3D holographic display.