Fiat ecoDrive

Fiat has an interesting gadget called ecoDrive. This is a free software program which analyzes your driving habits and makes suggestions how you can change them to save more fuel. What is cool is how it does it--the car will write vehicle data (likely signals: throttle position, engine speed, vehicle speed) as you drive to a USB stick you plug into the car's USB port. The PC program will then analyze this data.

More here.