Bought a quite nicely looking early-2000s ATX case with floppy and two CD drives for an old computer, from classified ad. The only info about its history I got from previous owner was that he got it from local TV station when they thrown old things to recycling. However... I have no idea what was it used for. That's what I got:
 - No mainboard. Not removed, there was never a mainboard installed. No typical scratches on mainboard mounting points, no remains of fastening or these copper/bronze things to install mainboard, no rear bracket installed and no trace that it was installed. 
 - Not even single factory bracket removed from slot covers. All sitting in place.
 - In front, a sticker of a computer manufacturer/service which never existed.
 - AT power supply inside, with power wires shorted to turn on when the power is connected. The power is fed to power LED and CD drives only - even floppy drive is not connected.
 - Optical drives seem to be the only drives installed in this casing at least years ago and never replaced. Also not connected, dust on connectors, audio ones too.
 - And another strange thing: Looking into drives, their optics and mechanics parts look like new. However, when I look into tray mechanism, it almost falls apart.
So for some unknown reason, someone built a machine to bang CD trays back and forth and was actually doing it!