Good idea:
Large styrofoam camping cooler, 2 bags of ice.
Hole is one end of styrofoam, ducted to fan intake on case.
Hole in the other end of styrofoam (a little smaller) to let air in.
Depending on the CFM going through the styrofoam, you may not get as much coolness as desired. Perhaps two coolers on top of each other, with air in through the top one, down into the bottom one, and then into the case? Ice in top & bottom coolers?
Starting to sound like fun, now 🙂
--Woodie