If you want to really get into saving the earth, you should be driving a diesel car, as you can pump that thing full of earth-lovin' biodiesel. You are? Great! Now you need to start making your own fuel. No, it's really not that hard, you just need the right equipment.

Equipment such as the FuelPod 2, a contraption that can product up to 50 liters a day of biodiesel from waste cooking oil. Sure, you'll need to become friendly with your nearest short order cook to acquire that much cooking oil every day, but if you do you can run your car on biodiesel every day without ever using regular oil. You can't go wrong there.

Product Page, via Red Ferret