It's not that hard to build a CD player, actually.

All you need is the following:
  1. a laser
  2. a few integrated circuits
  3. resistors
  4. capacitors
  5. solder
  6. a rat
  7. a rat wheel attached to a CD spindle
  8. an ample supply of "processed cheese food" used as an award when the rat runs at the correct speed (that stuff will last for years before it rots -- the amount you use depends on how much you are planning to use the CD player.)
  9. and of course, an electric shock mechanism to punish the rat for running too fast or too slow.