Oh snap, I've got a whole page full of these in a joke book. Now, let's see...
Not the sharpes knife in the drawer.
Note the sharpest tool in the shed.
Not the brightest bulb on the christmas tree.
(S)he fell out of the stupid tree and hit all the branches on the way down.
One fry shy of a Happy Meal.
A few sandwiches short of a picnic.
A few sodas short of a six-pack.
A few grapes short of a bunch.
The wheel is spinning, but the hamster's dead.
The butter has slipped off his/her pancake.
The antenna isn't picking up all the channels.
The elevator doesn't go all the way to the top.
Wanna listen to me rant about stuff? I started a blog!
https://theloonybinblog.wordpress.com/