Although I haven't engaged in a beer-bout for quite some time, I remember chilling hot ones almost instantly with a blast of propane - or anhydrous ammonia.
Better yet, back in the good ol' days, one could simply pull through the drive-up liquor store window and exchange anywhere from 1 to a truckload of warm beer for the same cold, even-up.
Egad! I'm a fossil!
On the Mythbuster's show they tried numerous things. I think the myth(?) was using compressed air. They tried a fire extinquisher and some other fancy stuff. I usually dunk it in ice water for a few minutes. They did that, which came in second by a minute or two compared to SALTY ice water - which has a cooler temperature.
I can't remember how good a job the extinqisher did. But it sure was messy!