Here's a cool project that will surely appeal to all aspiring MacGyver fans out there. MAKE Projects has come up with a bottle radio that runs on thin air.
The idea is similar to the DIY crystal radio projects from yesteryear, except that this radio works without any power source. You'll need a variety of materials and quite a bit of wire in addition to a glass bottle to make it work. If you follow the steps below, you'll soon have an inexpensive, power-free AM radio in your hands: