http://makezine.com/23/

In this special GADGETS issue, we show you how to make a menagerie of delightful machines: a miniature electronic Whac-a-Mole arcade game, a tiny but mighty see-through audio amplifier, a magic mirror that contains an interactive animated soothsayer, a self-balancing one-wheeled Gyrocar, and the Most Useless Machine — the creepy mechanical box whose only purpose is to turn itself off (as seen on The Colbert Report!). Plus: how Intellectual Ventures made their incredible laser targeting mosquito zapper, how to use the industrial-strength microcontrollers called PLCs, and a lot more.