Toyota Prius. Then, after you've woken from your nap, you probably envision some complex system of batteries and electric motors and gears to capture power when braking and spit it back out when accelerating. Chrysler is now looking to deploy a different way, a seemingly much simpler way that's all based on hydraulics. The vehicle is outfitted with a low-pressure reservoir of hydraulic fluid and a high-pressure chamber filled with nitrogen gas. When braking, pumps move the fluid into the nitrogen chamber to compress it and then, when accelerating, that compressed gas is used to push the fluid and drive the wheels. It's a setup that was actually developed by the EPA and is currently in use by some commercial vehicles, most notably UPS trucks, but a hybrid Town & Country minivan could bring it to consumers -- though not until 2012 at the earliest. Now, there's a good chance the idea of a hybrid minivan is threatening to put you back to sleep, so we wish you pleasant dreams.