Automotive teeneager switch
A system that allows you to "switch" your vehicle to a "teenager mode". This would consist of a speed limiter for the engine so you can control vehicle speed, sensors on the seats to see if there are more passengers than allowed, and a GPS system that you can pre-program to set off an alarm (in the car and at home) if the vehicle enters and restricted area (ie. certain parts of town etc.) With teenage driving deaths at an alltime high, I feel this would be embraced by the insurance industry.
Reward: the actual product