I don’t think this one has been posted, but forgive me for not searching too well as many of the jokes weren’t really jokes at all, and thus boring. I did find the CAT scan one though.
A man buys a horse at a horse auction, only to find that he can’t make it go. He says “Giddyup” but it won’t move. So he brings it back to the auctioneer who says, “I forgot to tell you, it’s a religious horse. You have to say ‘Thank God to make it go, and ‘Amen’ to make it stop.”
So the guy says “Thank God” and the horse zooms off very fast – it races toward a cliff. But the guy forgets how to make it stop, so he says a prayer and, at the end of it, says “Amen.” The horse stops an inch before the edge of the cliff, and the guy says, “Oh, Thank God!”