[sammyg2]

A couple of my favorites with the explanation as I understand it (discaimer, might be urban myths but they makes good stories):

"Go the whole nine yards" is supposed to refer to the British fighter pilots in the battle of Britain. Seems the hurricanes they were flying had ammo belts that were nine yards long and their orders were to go the whole nine yards, in other words don't come back until you are dead or out of ammo.

"Cold enough to freeze the balls off a brass monkey" does not mean what you might think, it is resportedly traced back to the time of the great navy battles of Great Britain and Spain. A brass monkey was a box that was bolted down next to the cannon. It was square and designed to hold a stacked pyramid of cannon balls, which were often made out of brass.

In extremely cold weather, water would accumulate in the brass monkey and freeze. When the water turned to ice it expanded, causing the cannon balls to fall off the stack and roll around.