Make your own 4-in-1 car wiring diagnostic tool. The Uber Tester is a gadget that won't remove door panel clips but does test for most wiring conundrums you might encounter

The best way to learn how to make your own backyard biodiesel is to start with a one-liter batch. It's easy to make a small batch that will work in any diesel engine. You won't need any special equipment--an old juice bottle will serve as the "reactor" vessel--and on such a small scale, you can quickly refine your technique and perform further experiments

Want a better way to play MP3s through your car stereo than using an FM transmitter or a cassette adapter? Cut the static by connecting your iPod to your stereo's aux jack