wow, theres some good ones here.
but for me its
measure twice, cut once.
it stuck out like a bulldogs ballsack
or, youll stick out like a turd in a punchbowl
hot girls make us buy beer, ugly girls make us drink beer.
about as sharp as a rubber glove/2x4/balloon
thats about as useful as a screendoor on a submarine
These I learned in the army:
'bout as squared away as a football bat
Thats 'ate up like a soup sandwhich'
looks like a bunch of monkeys tryin to hump a football
or, "he couldnt hit the broad side of a barn, if he was IN it"
And the final one, me and my ranger buddy are very fond of...
I am more afraid, of an army of sheep led by a lion, than an army of lions, led by a sheep