IRC and Minecraft buddies Atdiy and whisk0r have been doing some cool videos on making cigar box guitars, some kind of neural network stuff, and more recently: some introductory electronics videos. After winding inductors and making their own capacitors in previous episodes, they get around to making their own foxhole radio just using a blued razor blade as the detector:

Pretty neat! If you like this kind of stuff, subscribe to their YouTube feed.