A few beers short of a six pack
A few clowns short of a circus
A few feathers short of a whole duck
A few fries short of a Happy Meal
A few peas short of a casserole
All foam, no beer
An experiment in artificial stupidity
An intellect rivaled only by garden tools
As smart as bait
Body by Fisher, brains by Mattel
Chimney's clogged
>Couldn't pour water out of a boot with instructions on the heel
Didn't ship out with a full seabag
Doesn't have all his Cornflakes in one box
Doesn't have all his dogs on one leash
Doesn't have both oars in the water
Doesn't know much but, leads the league in nostril hair
Dumber than a box of hair
Elevator doesn't go all the way to the top floor
Forgot to pay his brain bill
Has an IQ of 2, but it takes 3 to grunt
He fell out of the Stupid Tree and hit every branch on the way down
Her sewing machine's out of thread
His antenna doesn't pick up all the channels
His belt doesn't go through all the loops
If he had another brain, it would be lonely
Missing a few buttons on his remote control
No grain in the silo
One Fruit Loop shy of a full bowl
One taco short of a combination plate
Proof that evolution can go in reverse
Receiver is off the hook
Several nuts short of a full pouch
Sky light leaks a little
Slinky's kinked
Surfing in Nebraska
The cheese slid off his cracker
The wheel's spinning but the hamster's dead
Too much yardage between the goal posts
Warning: Objects in mirror are dumber than they appear