Dad: "Do you think that if we went up to the moon, took the remains of the base, the little moon cars, gathered up all the golf balls, and took the American flag..."
Me: "It would be the greatest practical joke of all time."
Dad: "...do you think that would be stealing?"
Me: "...well, no. They don't actually own the moon."
Dad: "But the equipment?"
Me: "In all fairness, they did abandon it."
Dad: "Salvage, then."
Me: "We could replace the flag with a picture of someone mooning..."
Dad: "Or the flag of the moon! The Lunar flag!"
Then the conversation turned, somehow, to Heinlein, and the origin of "lunatic", and he went downstairs to get bread from the freezer.
And then he fell up the stairs.
Don't ask me. I'm not entirely certain how.