A man buys a lie detector robot that slaps people in the face when they lie. He takes it home to test out.
At the dinner table he asks his son "Where were you today?"
"At school," the son replies and the robot slaps him in the face. "Okay, okay I was watching movies at Joey's!"
"What movie were you watching?" questions the dad.
"Just a cartoon," replies the son and again the robot slaps him in the face.
"I said what movie!" says the dad and the son replies "It was a porno."
"What?! When I was your age we didn't even know what a porno was!" says the dad.
The robot slaps him in the face.
The mom speaks up "Well he sure is your son."
The robot slaps the mom in the face.