As retold by Bruce Lowitt

Leo and Rachel, both in their 60s, show up at a doctor's office and explain that they're concerned that their  age is sapping their interest in sex, and would the doctor mind checking them out?

The doctor says yes, they go into an examination room, the doctor checks and finds nothing wrong, then he gives them some erotic literature and tells them he'll be back in 20 minutes to see how they're doing.

When he returns, Leo and Rachel are going at it like rabbits. Everything's great, they say. The doctor presents his bill and they leave.

A week later they're back with the same complaint. Another exam, more literature, another 20 minutes, another bout of lovemaking, another bill and they're gone.

When they come back the following week and go through the same routine, with the same results, the curious doctor says, "Look, you're both healthy and your sex life is, too. What I don't understand is why you keep coming back?"

Rachel says, "We're married, but not to each other. We and our spouses live in a Senior Center. Everybody knows everything about everybody. There's almost no privacy. The cheapest motel room goes for about a hundred dollars."

And Leo says, "You charge about half of that for an  office visit. Where else could we do this 
for $60 and get $48 back from Medicare?"