from
Jargon File (4.4.4, 14 Aug 2003)
case mod
[from `case modification']
1. Originally a kind of hardware hack on a PC intended to support
{overclocking} (e.g. with cutouts for oversized fans, or a freon-based
or water-cooling system).
2. Nowadays, similar drastic surgery that's done just to make a
machine look nifty. The commonest case mods combine acrylic case
windows with LEDs to give the machine an eerie interior glow like a
B-movie flying saucer. More advanced forms of case modding involve
building machines into weird and unlikely shapes. The effect can be
quite artistic, but one of the unwritten rules is that the machine
must continue to function as a computer.