Control computers with your tongue.

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The Tongue Drive System is an invention which allows those with severe spinal cord injuries or neuromuscular diseases to operate a computer or wheelchair with their tongue.
A tiny magnet the size of a grain of rice is implanted under the tongue and utilizes an array of magnetic sensors which lead the movements of the tongue to control the computer.
http://www.geek.com/control-a-wheelchair-or-computer-just-with-your-tongue-20080701/