After seeing this link to a clever crystal radio made out of a CD spindle over at Hack-a-day, I looked through some of my old bookmarks to find a few more ‘free radio’ links. The Xtal Set Society is like your one stop shop for parts and kits if your interested in learning about how to build crystal radios. If you didn’t know, a crystal radio is a radio that does not require any power source other than the AM broadcast signal itself to operate. Anyone that likes to tinker should build at least one of these, what’s cooler than something that works for free? Another great site for information is Crystal Radio Resources. I bet you didn’t know you could build a crystal set to receive shortwave radio did ya? Who knows, you might want to cheat a little and build a simple amp for your crystal set just to make it easier to hear over the noise of your computer.