Youtube link to a video in the title, showing off what the Media Computing Group is calling Madgets. These things are pretty neat, though they need to run on a custom built surface at the minute. Essentially these guys have layered together an LCD screen, a bunch of electromagnets and a camera for object detection into a very impressive input/output device. Watch the linked video, it explains what they've done very clearly.
I can envisage a lot of situations where this would be really handy. I'd love to have a giant touchscreen desk as my main computer interface. Having the ability to add little actuated controls would be fantastic. Imagine working with a mouse (mice are still much better for some input tasks) then just flicking it off to a corner of the desk when you don't need it. When you do want it back, you could just gesture on the table/screen and the mouse would come scurrying back to your hand. Or being able to hit a key and have all your input devices move out to the edges of the table to leave you a completely clear screen to work with. Tap another button and the devices (mice, keyboard, dials, whatever) all rearrange themselves back to their home locations.
Get it to market guys!