I was at the local grocery store, and on the shelf I saw a Lite-Brite cube. What was my immediate thought? "I wonder if I could put a PC in it."
The base of the cube came with two drawers, and a space in between where the light bulb came up. I used a dremel to cut away the space in the center, and to trim one of the drawers to a false front.
The motherboard is a mini-itx size board, with an integrated 533 MHz EPIA processor. The board is fairly inexpensive, and does not require a fan. There's no room for a CD-ROM, but I can use a USB CD-ROM when needed. You can see the motherboard I used here.
Obviously, this is not a gaming computer. My plan is to use it as a server, and also for playing music.
The power supply actually snaps onto the motherboard, and has an external AC to DC converter. You can see the power supply I used here and the external AC to DC converter here.
The hard disk is mounted to a plastic strap that I stretched across the base. This is not meant to be a portable device.