Two guys went to a gas station that was holding a contest: a chance to win free sex when you filled your tank. They pumped their gas and went to pay the attendant.
"I'm thinking of a number between one and ten," he said. "If you guess right, you win free sex."
"Okay," agreed one of the guys, "I guess seven."
"Sorry, I was thinking of eight," replied the attendant.
The next week they tried again. When they went to pay, the attendant told them to pick a number.
"Two!" said the second guy.
"Sorry, it's three, said the attendant. "Come back and try again."
As they walked out to their car, one guy said to the other, "I think this contest is rigged."
"No way," said his buddy. "My wife won twice last week."