Riddle: An electrician and a plumber are waiting in line to get in to a movie. One of them was the father of the other's son. How could this be possible?
Answer: The plumber and electrician are husband and wife.
Riddle: A man and his wife were driving through a forest. They got out of the car to have a picnic. The man killed his wife, and laid her by a nearby tree. He then packed up the picnic and left. Later that day a police officer called telling him that his wife had been killed and that they needed him to meet them at the scene of the crime. When he arrived the officer immediately knew that he was guilty. How?
Answer: The officer did not tell the man where his wife had been killed, so when he showed up, they knew it wa him.