[Doglips]

Useful Descriptions For People
Not the sharpest knife in the drawer.
Got into the gene pool while the lifeguard wasn't watching.
A room temperature IQ.
Got a full 6-pack, but lacks the plastic thingy to hold them together.
A photographic memory, but the lens cover is glued on.
A prime candidate for natural deselection.
Bright as Alaska in December.
During evolution his ancestors were in the control group.
Fell out of the family tree.
Gates are down, the lights are flashing, but the train isn't coming.
Has two brains; one is lost and the other is out looking for it.
He's so dense, light bends around him.
If he were any more stupid, he'd have to be watered twice a week.
If you stand close enough to him, you can hear the ocean.
It's hard to believe that he beat 100,000 other sperm.
Some drink from the fountain of knowledge, but he just gargled.
Takes him 1.5 hours to watch "60 Minutes".

[Big Dog]

"He's a 40-watt bulb in a string of hundred watters."

"He's proof positive not all abortions work." (I actually used this on a young feller once, in public!)

" A legend in his own mind."

[sparrow]

A few ants short of a picnic.

[Despoiler]

So narrow minded that his scratch pads are only an inch wide.

Poster child for abortion.

when he fell out of the stupid tree, he hit every branch on the way down.

[toolman]

Looks like his daddy 'cause they had the same cousin.
Thinks dog crap qualifies as scooby snacks.
She's got her momma's butt-all 100 lbs of it.
Not smart enough to be a mudflap on the stupid truck.
And my favorite, ala Hank Hill: That boy just ain't right!

[NRAJOE]

Brad Pitt might have 6 pack abs, but I got a full keg baby!

[Bookman]

Great list, Doglips!

Here's one I've always liked: " A few yards short of a first down".

In England they say "a few pence short of a full pound"

Let me modify one of your sayings:
"A room temperature IQ. On the Celsius scale"

[MAX7.62]

A few french fries short of a happy meal.
His biscuits ain't done.
and - as we say in the south - he's just plain"ignernt".

[pmspinnerb8]

Not enough chlorine in that gene pool, is one of my favorites.

[toolman]

His butter done slipped off his biscuit.

[SPOCAHP ANAR]

Has hit rock bottom and started to dig.