One-wheeled Motorcycle

Wow wow!

"The EMBRIO Advanced Concept is a one-wheeled recreational and commuting vehicle for the year 2025, designed by the Canadian company Bombardier Recreational Products. Although the riding position is similar to that of a motorcycle, the vehicle uses sensors and gyroscopes to balance up to two passengers on a large single wheel whilst driving. 

Although the vehicle will also remain stable when motionless, with two small front wheels deployed at speeds below 20 kilometres per hour (12.5 mph). To move forward, the rider activates a trigger on the left handlebar. At a speed of 20 kilometres per hour (12.5 mph) the front wheels or “landing gear” retracts so the rider is balancing on the large single whe

el. To turn the rider leans to the left or right. The brake is activated by a trigger on the right handlebar. Fuel cells running on hydrogen provide electricity for the electric motor which drives the single wheel."

Source : http://thecontaminated.com/embrio-one-wheeled-motorcycle/comment-page-1/

And here's another :

Source : http://technabob.com/blog/2008/04/25/the-uno-motorcyle-meets-segway/

And another interesting model ...