Once when I needed to entertain my daughter while we were driving somewhere, I said, "Let's pretend that, rolling along outside the window, there was a little ball that would pick up trash and boxes and trash cans, and that as it collected items it got bigger and bigger, until it was picking up houses and buildings, and that there was happy music playing that sounded like this (I hummed a bit), while hundreds of citizens called out for help that would never come."
Her little eyes got really wide.
She was very quiet for the rest of the ride.