When most people opt to use water cooling they put together tidy coolant reservoirs complete with ambient lighting and the like. This build involves a hole in the wall and the tank of a functioning toilet.
The design, courtesy of Jeff Gagnon, is unconventional, but effective. Opposite of his wall-mounted PC is a bathroom. In that bathroom he has a coolant pump in the tank of the toilet. Using the toilet tank as a thermal sink he keeps the CPU at a nice chilly 66F. Hit up the link below for more pictures, including a peek inside his hacked together toilet-tank cooling rig.
How to Cool a PC with Toilet Water [Extreme Tech]