A guy goes to his doctor and says, "Doc, I have a problem. My girlfriend is sleeping over this Friday, my ex-wife is sleeping over this Saturday and my wife is coming home Sunday."
"I need 3 Viagra pills to satisfy them all."
The doctor says, "You know 3 Viagra pills 3 nights in a row is pretty dangerous for any man. I will give them to you on the condition that you return to my office on Monday so that I can check you out."
The man says, "You have a deal Doc."
Monday morning the man returns with his arm in a sling.
The doctor asks, "What happened"?
The man answered, "Nobody showed up!"