Bite the bullet
You often see in period dramas that they have women bite on wooden spoons while giving birth. Well, it's claimed that in war time they had soldiers bite on a bullet to take their mind away from the pain of their surgery; ie amputating a limb.
Kick the bucket
When someone would commit suicide by hanging, they often used a bucket which they would kick to hang them self.
Face the music
The expression “face the music” comes from the military “drumming out” ceremony for disgraced soldiers. This ritual called for only drums to accompany the dishonored as he was stripped of his rank and colors in front of his assembled unit. For cavalrymen, this humiliation was enhanced by having the offender sit backwards on his horse so that while leaving he could still see, as well as hear, the drums and the band.
Drunker than a skunk
This appears to be a fairly modern phrase. Despite what you see in the movies, it seems that the earliest use of the phrase didn't start until the 20th century.
The best that anyone can guess, it seems to be based on the fact that it rhymes and that skunks and drunks stink.
Caught red handed
This is being caught with the blood of your victim on your hands.
Got up on the wrong side of the bed
This is a Roman superstition. It's bad luck to to get out of bed on the left side. Doing so will make you grumpy all day long.
If you notice, day beds are made so you can't get out on the left due to it having a back on that side. You can only get out on the right side.
Under the weather
It was believed that weather can make you sick, so you were under the influence of the weather or more commonly "under the weather".
