Nils Ferber and colleagues created an unusual motorcycle powered by battery-powered screwdrivers drills. The two 18-volt screwdrivers drill are apparently good enough an engine to accelerate the bike to 30 km/h (18.6 mph).

Both screwdrivers run in the same direction to get the maximum power out of them.
To avoid one screwdriver blocking the other, overrunning clutch gearwheels are used to transmit the torque.

See more at Nils' website: Link - via The Presurfer