Preschool, they're hopefully very restricted on screen time, and might not want to encourage that.
With a bit older kids, once they're all allowed to use smartphones, tablets, or video games, showing them they could make a game, using kind of pedagogic morphs world platform (maybe Squeak or Scratch), could be great. You can let them show them something like how to make a car or character of shapes and make it move somehow, then ask for more ideas and live-implement them. (Try for direct manipulation and concrete and visual, minimizing textual/block code as much a possible.)
With a bit older kids, once they're all allowed to use smartphones, tablets, or video games, showing them they could make a game, using kind of pedagogic morphs world platform (maybe Squeak or Scratch), could be great. You can let them show them something like how to make a car or character of shapes and make it move somehow, then ask for more ideas and live-implement them. (Try for direct manipulation and concrete and visual, minimizing textual/block code as much a possible.)