A team of undergrads at MIT -- led by Shakeel Avadhany and Zack Anderson -- has produced a prototype of a shock absorber for vehicles which can harness and generate electricity back into the vehicle. The team claims that their prototype increases a vehicle's fuel-efficiency by up to 10 percent by using a "hydraulic system that forces fluid through a turbine attached to a generator." There is an active electronic system for controlling and optimizing the damping for a smoother ride than regular old shocks. The team is actively seeking to develop and commercialize the product, and have already seen interest in the prototype from the United States military and also several manufacturers of trucks, which see the most benefit from the shocks... so look for these guys on Grave Digger any day now.