A man wakes up one morning feeling too ill to go to work. So he phones his boss to call in sick.
"You won't believe this," says the boss, "but I felt exactly the same last week. I went home, made love to my wife and in two hours I felt much better."
After three hours the man phones back sounding much perkier than before.
"You were right, it really did work. I feel much better now," he explains. "Oh, and by the way, nice house!"