The Microsoft Kinect is a controller that sits on your XBOX and allows you to play games without having to hold any controller at all. The cameras inside can pick up all your body movements and translate them into actions.
Naturally hackers all over the world thought this shouldn't be confined just to the XBOX and so have been modifying it to run on countless other applications. Rasomuro decided that it would be great for controlling a NXT robot.
In his hack, he controls the robot by 'pretending' to move two levers. The Kinect picks up the body movements and translates them into commands for the NXT.
More info on his page - http://rasomuro.org/20110326.html
via - KinectHacks