The Smart Retina project is pretty cool. Basically a gesture based computer interface, but one that actually seems to work, at least in lab type environments. Not sure how long it would last in an office full of idiots all flailing around like Kermit the Frog. Check the video with the Google Earth demo.
The above video demonstrate how Smartretina can be used as a navigating tool combined with Google earth. SmartRetina (working on the black laptop on the right) captures the user’s hand gestures, understanding them as computer actions such as up, down, left, right, Zoom In etc, then sends the commands to a computer running Google earth (the desktop on the left).