Jump the gun during the American Civil War, many Union soldiers would be riled up to such frenzy that they would charge into battle before the cannons cleared away the brunt of the treasonous scum, a choice usually ending in their rapid demises. These soldiers often bounded over the lines of cannons in their frenzy, and were said by the more sane soldiers to have 'jumped the gun.'
Kick the bucket in the middle ages, during a primitive surgery, doctors would often put buckets on the feet of their patients to make fun of them while they performed delicate operations. Often the pain the doctors caused their patients due to the period's dumb medical theories would cause patients to flail their feet around before succumbing to the doctors' poor skills and going to Heaven. The patients as they died were said by the presiding doctors to have 'kicked the bucket.'
Bring home the bacon in precolonial Hawaiian history, the wild pigs of the islands were of such abundance that for long periods of time their meats were used as currency; at one point a strip of bacon, adjusted for inflation, was worth about thirty dollars. The workers of the islands hoped through their toils that they could 'bring home the bacon' to their loved ones.
Dont give a damn During the final judgment, God will be overwhelmed with the immeasurable number of boring people who were utterly unremarkable in both their sins and virtues. Because He won't care enough, and will just want to get it over with, He will allow them eternal salvation, and won't send them to Hell. He will be said not to have 'given a damn.'