Build your own TDR out of a scope and a signal generator to troubleshoot long cable runs and impedance mismatches.
Learn all about Thevenin's Theorem and its application in analyzing circuits with dependent sources.
You can buy cheap 433MHz RF modules from Mouser and DigiKey. This article will show you how to use them with a PICAXE microcontroller to hack your own mousetraps.
Disney's joined the augmented reality market and it could be the critical mass needed to bring the technology into the average home.