I always thought the most compelling part of driving a Prius was the little screen that showed you when you were using gas versus electric. Sounds like Chevy has taken that idea a step further with their Volt interface:
Its designed to give you real-time feedback on your driving style. When the car is happy i.e. being driven efficiently, the ball is green and in the center of the gauge. Stomp on the accelerator, and it rises to the top, changing color to yellow. Brake too hard so youre bypassing the kinetic energy recovery and it dives to the bottom, again changing color to yellow. The more time you spend in yellow, the fewer miles youll go before you have to start burning hydrocarbons.
For all the stupid talk about gamification, this seems like the real thing: A feedback loop that naturally helps you get better at something.