A few in relatively standard American usage have been, uh, altered by my exposure to another dwellar ...

"Useless as tits on a left-handed monkey" and "Come Hell, high water, Hitler, or the Second Coming of Christ" are two of the most memorable.

"Sucks moose cock" is one of my own.

I've been trying very hard to come up with some more of these, but I think because they are in such common usage, that I don't even consider that they are typically American phrases.

The boys at work looked at me funny when i said "jeezly fuck" the other day - thanks 'spode.

I was impressed when I read it, and it must of stuck on some level.

Dull person=personality of roadkill

Taking a dump (which may be an Americanism itself)= Dropping the kids off at the pool

Cheese and rice=Jeezus Christ

Anything Foghorn Leghorn ever said.
The real McCoy was about the inventor of the first decent combustion engine... a free black man.
"is it a good-un?"... "it's a' real McCoy".

My father-in-law has some good ones:
"Finer than frog fur"
"Back when Hector was a pup"
"Older'n'dirt"
"I've got underwear that's older than you!"

My grandma says "finer than frog hair."

Also "colder than a popcorn fart."

What about not knowing the difference between "your ass and a hole in the ground"?

That's the first time I ever heard that explanation, must be an Ohio thing. Here it means taking a crap. :blush:

Are you being silly? You do know I meant:

Taking a crap="dropping the kids off at the pool."

I couldn't figure out how to say it without using a various number of other Americanisms! :blush:

Some of these are southern, some aren't. I don't know which are which anymore. Levels of humor also vary....

"She looks like a bag of cats headed for the river"

"If he was playing for syrup, he wouldn't get a sop"

"He smelled so bad he'd knock a buzzard off a gut wagon"

Bodacious (I've only ever heard it used in reference to food, but it has other connotations apparently).

"You look like the frazzled end of hard times"

"You look like the morning after the night before" (for hangovers)

"He's all hat, no cattle"

"He doesn't have the sense God gave a billy goat."

"You make a better door than a window" (you're blocking my view)

"What, do I look stupid?" (or "What do I look, stupid?" -- never knew how to phrase it right) -- this always sounds like it should be said with a Brooklyn accent, to me.

"Get off your high horse"

"Fool me once, shame on you; fool me twice, shame on me"

"You writing a book? Leave that chapter out" -- when asked a prying question.

"If you had dynamite for brains, you wouldn't have enough to blow your nose"

Great one. Nobody likes a fake-ass cowboy.

It's been used much for Bush. I thought Ann Richards had used it, but I couldn't find reference. However, I liked this one:

"Poor George. He can't help it. He was born with a silver foot in his mouth."

Either she had trouble with his accent or she was just a bim in general - it's not a common phrase over here, but it's not unheard of. My Uncle certainly used to use it when we had buffet style meals, "Right, I think I'm all set" when he'd filled his plate.

Hide the Sausage
 

A euphemism for...uh, you know!

As in "Wanna play hide the sausage?"

I can guess which thread you've come from without even stalking you! (but I'm off to check anyway)