I've known some computer geeks that have tried some really out there ways to cool their PC. One dude used a massive copper pipe system buried in the snow outside to cool the liquid for his computer to some cold temperatures for overclocking. A guy over on Hack A Day has come up with a way to suck cold air from outside into his PC to cool things down.
The system is really simple and uses a coiled hose from a dryer along with the dryer vent hood that goes on the outside of a house and a piece of wood. The wood has a hole cut in it and a green Scotch-Brite pad was used as a filter to keep bugs and debris from getting into the computer.
A fan inside the machine in a puller config sucks the cold air from outside the house into the computer. The only thing I wonder about is condensation inside the machine. This proves geeks will do just about anything to get more performance from their computers.