At one time I got a broken MagSafe power supply, the ones that Apple ships with their laptops. Since I was curious how these switched-mode power supplies work, I cracked it open and somehow shorted the big capacitor. These temporarily store up to 400 volts but it wasn't that much left. I still got quite a zap, though :-)
Anyway, I got a big crate of broken ones from a local Apple dealer in town. I found out that they usually didn't work because the wire would break close to the adapter. eBay sold replacement cables and I started fixing the power supplies. Cracking them open, replacing the cord, testing them, glueing them shut as neat as possible, then selling them for 25 bucks.
It was fun but with a kid on the way, I had no room for a separate table for my soldering iron, electronics stuff etc. and I stopped doing it. Cleaning up every time you want to do something small isn't fun.