How differentials work
GM put together this video in the 1930s that gives an excellent, clear demonstration of how a differential works. Skip to 1:50 into the video for the good stuff. (source: http://jalopnik.com/5335841/how-does-the-differential-work)Hybrid cars as emergency generators
http://lifehacker.com/5118575/use-a-prius-as-an-emergency-generatorHydraulic drivetrains

Fuel-saving "series hydraulic" drivetrain developed by Eaton:
http://www.eaton.com/EatonCom/ProductsServices/Hybrid/SystemsOverview/SeriesHydraulic/index.htm
Disappearing car door

See how it works at http://www.disappearing-car-door.com/
(via braindump.posterous.com)
