Leave it to a college student to figure out how to make cheap homemade air conditioning.

http://mirror.lerfjhax.com/www.eng.uwaterloo.ca/~gmilburn/ac/ 

HoMEbrew A.C.

Looks pretty cool, but I ain't so sure about the cost-effectiveness of it. Central air, per square foot, is probably cheaper.

I'd say that this was well thought out, and it certainly provides some limited cooling, but it's dependant on the amount of ice and water in the trash can, and once siphoned out, cooling is done. And what about the mess outside the door? Let someone else worry about that.

I say...whatever works for you.