You couldn’t organize a stampede toward the exits at a Dick Cheney striptease act.
was that really necessary?
I always heard it as “you couldn’t organize an orgy in a whorehouse.”
I’ve never heard that particular construction; my grandmother always said, “You could tear up a cannonball in a sandbox with a rubber hammer.” Usually said in relation to something my stepfather had done.
The favorite of an old boyfirend: You couldn’t organize a two-car funeral half a block from the cemetery.
I don’t know about you, but I’m so organizationally challenged I can’t:
Organize a prayer chain in a Baptist Church
Organize a blow job on prom night
Organize a cheap wedding in Vegas
Organize a doughnut run in a precinct house
I was gonna say: You couldn’t organize a piss in a pub. But **One And Only Wanderers
** beat me to it. 
I couldn’t and didn’t. ;( Her best friend supplied condoms, I gave her weed and cocaine and drove her to the best after-prom party. Problem: She had started showing interest in me a long time before the prom and when I didn’t return it she started dating another dude, and she was still dating him when prom came around. Looking back, I wasn’t as interested in her as I apparently convinced myself on prom night, so I guess I was leading her on and it was smart of her not to let it go any further. I blame the cocaine. (Actually, I was just a cocky and insecure bastard.)
Hey, wait, we’re in an insult thread. Sorry. Carry on.
You couldn’t organize a hoedown in America (land of hoedowns).
Morbid, and really, really gross. (So I’m putting it in a spoiler box)
He couldn’t organize a BBQ at a crematorium.
You can’t find your ass with both hands, even if your fingers are flashlights!
A Northern Irish one: you don’t know if it’s New York or New Year.