(YouTube Link)
The Berlin Brain-Computer Interface uses signals picked up by an electroencephalogram (EEG) to give commands to machines:
While the player imagines left and right hand movements, algorithms decode his brain activity signals in realtime into control signals for the pinball machine. The demonstration shows the cutting edge performance of a brain-computer interface system with regard of timing precision of the control signal. Other (slower) applications are developed for communication needs of e.g. paralized patients.
Link via Make