An old man went in to see the doctor and said, "Doc, I'm turning
eighty tomorrow. I've hired a hooker for the night, and I'd love
to do it just one more time before I die. Can you give me
something that'll get me up?"

The  doctor smiled. "I don't normally prescribe this stuff, but I
think in your case I can make an exception for one night."

Later that night, out of curiosity, the doctor phoned the elderly
man and asked, "How's it going?"

"Fabulous," the old man said. "I've come three times already."

"That's great," the doctor said. "the hooker must be astounded."

"Not exactly," the  old man said. "She's not here yet!"