Half-deckerisms are euphemisms that convey the "he's playing with only half a deck" idea. For example:

1. A few clowns short of a circus.
2. A few fries short of a happy meal.
3. The wheel's spinning, but the hamster's dead.
4. All foam, no beer
5. The butter has slipped off his pancake
6. The Cheese slid off his cracker
7. Body by Fisher, brains by Mattel
8. Not the coldest beer in the fridge.
9. Couldn't pour water out of a boot with instructions on the heel.
10. He fell out of the stupid tree and hit every branch on the way down.
11. As smart as bait.
12. Doesn't have all his dogs on one leash.
13. Her sewing machine's out of thread.
14. One fruit loop shy of a full bowl.
15. Her antenna doesn't pick up all channels.
16. His belt doesn't go through all the loops.
17. Some drink from the fountain of knowledge, but he just gargled.
18. Receiver is off the hook.
19. Not wired to code.
20. Skylight leaks a little.
21. Her saliency's chinked.
22. Too much yardage between the goal posts.
23. Got a full 6 pack, but lacks the plastic things to hold them together.
24. A photographic memory, but the lens cover is on.
25. During evolution his ancestors were in the control group.
26. Gates are down, the lights flashing, but the train isn't coming.
27. So dense, light bends around her
28. If brains were taxed, he'd get a rebate
29. Standing close to her, you can hear the ocean.

In the middle of a forest, there was a hunter who was suddenly confronted by a huge, mean bear. In his fear, all attempts to shoot the bear were unsuccessful. Finally, he turned and ran as fast as he could. The hunter ran and ran and ran, until he ended up at the edge of a very steep cliff. His hopes were dim. Seeing no way out of his predicament, and with the bear closing in rather quickly, the hunter got down on his knees, opened his arms, and exclaimed, "Dear God! Please give this bear some religion!"
The skies darkened and there was lightning in the air. Just a few feet short of the hunter, the bear came to an abrupt stop and glanced around, somewhat confused. Suddenly, the bear looked up into the sky and said, "Thank you God, for the food I am about to receive...."

A Brit, a Frenchman and a Russian are viewing a painting of Adam and Eve frolicking in the Garden of Eden.
"Look at their reserve, their calm," muses the Brit. "They must be British."
"Nonsense," the Frenchman disagrees. "They're naked, and so beautiful. Clearly, they are French."
"No clothes, no shelter," the Russian points out, "they have only an apple to eat, and they're being told this is paradise. They are Russian."

Jesus said: Love thy neighbor.
Elvis said: Don’t be cruel.

Jesus is the Lord’s Shepherd.
Elvis dated Cybill Shepherd.

Jesus is part of the Trinity.
Elvis’ first band was a trio.

Jesus walked on water.
Elvis surfed.
(Blue Hawaii, Paramount, 1965)

Jesus’ entourage, the Apostles, had 12 members.
Elvis’ entourage, the Memphis Mafia, had 12 members.

Jesus was resurrected.
Elvis had a famous “comeback” TV special.

Jesus said: If any man thirsts, let him come unto me and drink.
Elvis said: Drinks are on me.
(Jailhouse Rock, MGM, 1957)

Matthew was one of Jesus' biographers.
Neil Matthews was one of Elvis’ biographers.

Jesus’ countenance was like lightning and his raiment white as snow. (Mt 28.3)
Elvis wore snow white jump suits with lightning bolts. (Las Vegas, 1968)

Jesus taught of grace in a near eastern land.
Elvis lived in Graceland in a nearly eastern state.

Jesus was first and foremost the Son of God.
Elvis’ first recorded with Sun Records; today they are considered to be his foremost recordings.

Jesus was the Lamb of God.
Elvis wore mutton chop sideburns.

Jesus’ Father is everywhere.
Elvis’ father was a drifter, and moved around quite a bit.

Jesus was a carpenter.
Elvis’ favorite high school class was wood shop.

Jesus said: Man shall not live by bread alone.
Elvis liked his sandwiches with peanut butter and bananas.