Lego builder Simon “Burf” Burfield built the world’s first Lego wheelchair:

Currently still a prototype, the LEGO Wheelchair can move a 90kg person.

It uses 6 NXT’s to drive 12 NXT motors (2 per NXT for maximum power output) which are connected to 12 Rotacaster multi-directional wheels. Using these wheels will later allow for side to side movement(strafing).

There is a master NXT which controls the 6 NXT via turning on/off touch sensors. The joystick is connected to 4 touch sensors to determine direction (forward, backwards, turn left, turn right).
The master NXT then turns 2 motors (left / right side) different directions which turn on / off 12 touch sensors (2 per NXT for backwards / forwards).

Special thanks to LEGO and Rotacaster.com.au for supporting this project.

Man, he uses a ton of 64178s and 64179s! See the Flickr set for more goodness. [via The NXT Step]