An old couple go to a doctor and ask him to watch them have sex and tell if he see's them doing anything wrong. So they have sex. While they are getting dressed the doctor said, "Well I don't see anything wrong!"

A week later they come again and ask the doctor to watch to see if they are doing anything wrong. They have sex and the doctor says, "Well again I don't see anything wrong."

This goes on for weeks. Then the doctor asks why they keep coming.

The guy said: "If we go to her house her husband will catch us. If we go to my house my wife will catch us. A hotel costs fifty bucks. Here it's thirty-five dollars and medicare pays half!"