The famous 'Freezing the balls off a brass money' which comes from the days of sailing ships carrying cannon. the cannon balls were stacked in a pyramid formation, on top of a brass ring called a brass money. In extremely cold weather, the brass in the money would contract sifficiently for the monkey to shrink, and the balls to roll off, hence the saying. This has been disputed on this Site, but I think it sounds reasonable, and quote it when ever I want to sound like a boring show-off - which is quite often!