ne1 have fun projects for CPU PS?

As I just replied in another thread...they're not exactly suitable for audio use. The voltage is too low. There's not usually anything like a decent negative rail. Your best bet is probably to put a junker car amplifier on the +12VDC output. Don't try to draw too much current or you'll blow the supply.
If you like the sound of car amplifiers, you'll probably be happy. If you're hoping for something more along the lines of home hi-fi, you may end up being dissapointed.
You can always use it as a door stop.

they make great 12 volt supplies.about 10 to 20 amps available. If you want to part them out, you can get.....
-cooling fan
-IEC socket (if it's a good supply, it'll be a socket with integral EMI filter, or a regular socket with some caps and coils on a board)
-a pair of 200 volt caps that are at least 220 uF, or a single 400v if an active PFC supply
- power switch maybe
-some power wire
In theory, you could rewind the transformer for higher voltages, IF you can take it apart (the cores are ferrite, so very brittle, and they are glued together). The rectifier part would then also have to be changed for higher voltage diodes and caps, and the feedback for the regulator adjusted. I've done this before, and frankly, it is a PITA but it works.
Other than that, there are quite a number of useful parts in there, in addition to the already menationed, often times you can find 1-3 power fets, 7805, 7812 and 7912 regulators, HV caps, low ESR low voltage electrolytics, small chokes, etc.