and you don't have one?
Learned a new trick this last weekend at an event appropriately called "man vs. dirt".....
If you want a cold beer, and all you have is warm, there is a solution. I did't believe it when I heard it (nor did any of the other 30+ dudes around), but it's true.
Take your warm can or bottle of beer, place it on its side on a bed of ice, then simply roll it (barrel roll) on the ice for two minutes. The result is beer plenty cold enough to drink. Didn't believe it, and never would believe it, if I hadn't seen it (and drank it) myself.