Here's a good one from Arch's link.

beer \'beer\ n pl - Constant singular of "beer";
"I had ten or eleven beer even before I got to the Legion."
Never is the standard plural "beers" used in any conversation concerning a drinking event: doing so immediately identifies the speaker as being "from away."

nervers as a whore in church.

Colder than a well diggers ass in Montana.

Raining like a cow pissing on a flat rock.

our latest heros from FT. LEWISgod BLESS OUR TROOPS AND THANKS TO THEM WE ARE STILL AMERICA

for DD: slower then molasses running up a hill in January.

Amen, Mona!!

Take time today to remember our veterans and all our present military personal. They are our true HEROS.

Slicker than snot on greased glass
Round and round like the button on the $--- house door
Noises in the woods were always Rampareekuses, tree squeeks and side hill gougers.

DD
This little book will have a lot of the old sayings and they are cleaner than the ones I can remember.
http://www.dooryard.ca/index0.html

Speaking of slicker, here's one . . .

Slicker Than Snot

A few others . . .

Busy As A Bee, Sly As A Fox, There's No Time Like Now

Here's a long one from Tennessee Ernie Ford . . .

More Nervous Than A Long Tailed Cat In A Room Full of Rocking Chairs