Gyroscopic Car
Developed by a Ford designer and an aerospace engineer, the 1967 Gyro-x was a two-wheeled singleseater that used a spinning gyroscope to remain upright through corners. Theoretically, it would be capable of 125 mph, with a thrifty 80-hp engine saving on fuel. Gyro Transport Systems went bankrupt, but the car was saved and still works—though is limited to 30 mph.