The wheel's spinning, but the hamster's dead.

Half a bubble off of plumb.

The lights are on, but nobody's home.

He's a little too tall for his blood supply.

A few clowns short of a circus.

Takes him 1 1/2 hours to watch 60 minutes.

A few fries short of a Happy Meal.

Two tacos short of a combo plate.

Couldn't manage a two car funeral.

He's so dumb, he sits on the TV and watches the sofa.

He's so dense, light bends around him.