Medical researchers have discovered a new disease that has no symptoms. It is impossible to detect, and there is no known cure. Fortunately, no cases have been reported thus far.
- George Carlin

A knight and his men return to their castle after a long hard day of fighting. "How are we faring?" asks the king.
"Sire," replies the knight, "I have been robbing and pillaging on your behalf all day, burning the towns of your enemies in the west."
"What?!" shrieks the king. "I don't have any enemies to the west!"
"Oh," says the knight. "Well, you do now."