Hardware Hacking Introduction
So, you want to learn how to do some hardware hacking, eh?
I think that NTC's C.H.I.P. computer is a perfect device to learn how. Note I say "learn". There are many projects for which CHIP by itself would not be a good match (e.g. bit-banging a serial protocol with tight timing requirements). But CHIP is a wonderful platform for beginners, partly because if you accidentally destroy it, you're only out $9.
And let me tell you, if you stick with this hobby, you will eventually destroy something. You haven't earned your stripes until you see "magic smoke" rising from a project you slaved over.
The good news is that hardware hacking is generally a safe hobby. The voltage and current levels you'll be dealing with are generally not dangerous. Use some common sense (you'll burn your finger if you touch something that was smoking a moment earlier) and you'll be fine.
WIki user fordsfords has suggestions for outfitting your hardware lab: Fordsfords Beginner Lab.
See LED on solderless breadboard for a good "first" project if you've never done any hardware hacking before.