A man and a woman go to a sex therapist and asks the doctor if he'll watch them have sex. Puzzled, the doctor agrees. When the couple finishes, he admits there's nothing wrong with the way they have sex and charges them $50.

This goes on for weeks. The couple makes an appointment, has sex with no problems, pays the doctor, then leaves.

"What exactly are you trying to find out?" the doctor finally asks.

"Nothing," says the old man. "It's just that she's married, so we can't go to her house. I'm married, so we can't go to mine. The Days Inn charges $90. We do it here for $50, and I get $43 back from Medicare."