The MAV - Mono Axial Vehicle is a project aimed at building a 2 wheeled balancing vehicle that can function as a human transporter as well as autonomously.

 

Links

Other peoples auto-balancing vehicle projects:

JOE le pendule - from the guys at the LEI - Laboratoire d'Electronique Industrielle - Industrial Electronics Laboratory in Switzerland
http://leiwww.epfl.ch/joe/index.html

JOE le pendule's Relatives - many more links to other inverted pendulum type vehicles or robots
http://leiwww.epfl.ch/joe/joerelatives.html

autopilot: Do it yourself UAV (also uses gyroscopes and accelerometers)
http://autopilot.sourceforge.net/