A woman went to the doctor complaining of terribly bad knee pains. After the diagnostic tests showed nothing, the doctor questioned her, "There must be something you're doing that you haven't told me about. Can you think of anything that might be doing this to your knees?"

"Well," the woman said a little sheepishly, "my husband and I have sex doggy-style on the floor every night."

"That's got to be it," said the doctor. "There are plenty of other positions and ways to have sex, you know."

"Not if you're going to watch television, there ain't!" she replied