Little Johnnys Dad buys a lie detector robot that slaps people when they lie.
He decides to test it out at dinner on the first night.
Dad asks Little Johnny what he did that afternoon.... Johnny says, "I did some schoolwork." The robot slaps Johnny. Johnny says, "Okay, okay. I was at a friend's house watching movies." Dad asks, "What movie did you watch?" Johnny says, "Toy Story." The robot slaps Johnny. Johnny says, "Okay, okay, we were watching porn." Dad says, "What? At your age I didn't even know what porn was."
The robot slaps the father.
Johnnys Mum laughs and says, "Well, he certainly is your son."