I was given an old Apple II computer when I was about ten years old. I didn't do much with it exept playing some games for a while, and it just gathered dust in a corner.
I took this piece of history apart when I was bored one day. I kept the parts (esp. the power suply, as I knew it could be of use). Years later I took another look at it, and noticed this switching power suply could be of use, as it delivers 12V and 5V both positive and negative.
I drilled holes in the case and placed connectors (first only for the positive voltages, later I added connectors for the negative voltages, and added a LED power indicator, I used a lightbulb earlier, and it drew so much power the psu got hot). I use this power supply to power my digital circuits, and it's done a great job so far. It's unfused so a litle caution is necessary.
Note that these images are of the first version.
back of psu
front of psu
top of psu