The Embrio is a concept bike from Bombardier that kicks the ass of the Segway...and just about any other wheeled vehicle for that matter. Like the Segway, a gyroscope keeps you balanced on the thing, but unlike the Segway this only has one wheel! And it can supposedly take two people. One wheel + two people = big bargain! It's definitely got a lot going for it style-wise and balance-wise, but the idea of a hydrogen fuel cell seems a bit farfetched. It also comes with infrared night vision and a variable suspension, but sadly lacks a spare tire.
The small on the front keeps the Embrio "longitudinally stable", but it's only used when you start or stop. It retracts after you hit 12 miles per hour.