This is a design for super cooling using very little electricity. Granted, if you have an air conditioner sitting right next to the computer, you probably don't have our outrageous kilowatt-hour rate. (18 cents / kw HR). This is a design that incorporates pipes, a shovel (or a back hoe if you have one laying around) and fans. Quite simply it's like this:

Call your utility company and have them mark off the underground lines, water ways, etc. In our case, we still use telephone polls, and our water and sewer comes from the other side of the house, so we're all set.

Plot out where the pipes will lay. In the case of our house, we have a gigantic ditch running the width of our yard, so we'll be limited to going width-wise instead of going out and coming back. Not a big deal, just another couple of elbows needed.

It may also be feasible to simply run the pipes above ground, and bury them with topsoil, of course, if you were to do that, you may as well dig up the ground anyway, and replace the dirt there with fresh dirt. I reccomend going to Home Depot for all of your top soil, and piping needs.

You'll want to have as much pipe buried as possible. This is where your cooling is coming from. Right about the frost line is where you want to put these pipes. Here in Maine, it's 4 ft, so we dig down 4 ft, and lay the pipes. Simple as that. 

You need to figure out where the pipes are going to enter and exit your house. In our case, we're just going to run them out the window, and down to the ground. You'll want as little pipe above ground as possible to keep the air inside from warming back up. If necessary, you can wrap insulation around the pipes, but be sure to cover with some sort of plastic wrap that can withstand mother nature. If the insulation gets wet, it's useless. 

The enter/exit of our system looks like this:

Run your pipes up to the board, and seal them in place using a closet flange for a toilet. Then mount a fan to each hole, one blowing out to the pipes, and one sucking in. Depending on how much pipe you used, you may need a really high powered fan. 

Seal the fan to the pipe using either duct tape, silicone, or some such device. It will add to the force of the air moving through the pipes.

*It may not be necessary for a fan sucking air in. I do not have one like this, I have the pipes coming in and split off into 2" pipes to attach to the rear of the cases. the fans from inside the cases act as the intake fans.

Make sure that all of your pipes are SEALED COMPLETELY. This will keep mice, cockroaches, worms, snakes, and any other "things" from finding their way into your cpu. Not only will it keep out the varmints, but it will keep the odor of the dirt and any chemicals you put on your lawn out of your cpu where they'll be warmed up and stink worse. If you do not seal your pipes up completely, you're asking for trouble. 

You'll also want to seal the area between your pipes and the wall. This will keep unwanted air from reaching you, and will keep the pesky little bugs and things from doing the same. Just be sure that you get everything in place first, because once you seal it up, there's probably no easy way to get it undone. The Great Stuff, sprayble insulation, will work just fine for this, and will probably come in handy something else down the line.
 

Again, this entire section is experimental, and I have yet to complete the pipes. Although, I am working on the mass air exchanger, and the piping on the inside, I plan on running it under the desks, and I may just hang it from there. Sounds easier than trying to pipe each one individually, eh?