A salesman was travelling along a lonely stretch of rural road as the day was getting late and a storm was beginning. He saw a farm house up a head a bit and decided to see if he could spend the night there.

He pulls up in front of the house and knocks on the door. The farmer answers and the salesman asks if he can stay the night.

"Sure", says the farmer, "but you'll have to sleep with my son".

"Oops", replies the salesman, "I must be in the wrong joke".