You've Heard It Before
A travelling salesman's car breaks down in the middle of nowhere. He gets out and goes to look for help. Soon he comes upon a farm. Not believing his luck, he knocks on the door, and a farmer answers.
"Sir," says the salesman. "Could you help me? My car's broken down, and I need a place to stay for the night."
"Sure," says the farmer. "But I only have one bed, and my very, very ugly daughter sleeps there."
"Oh, crap," says the salesman. "I'm in the wrong fucking joke."