Cardboard Box City

Collect big boxes for a week — appliances and diapers come in the best ones. On playdate day, dump them in the yard or garage with markers, stickers, and packing tape. Then step back.

Kids will build houses, shops, tunnels, and at least one thing they refuse to explain. Resist the urge to direct. The chaos is the point; the city plans itself.

Add a 'mayor' election halfway through for maximum drama, and a parade through the box streets at the end. If you have a wagon, it becomes the city bus.

Cleanup is the beautiful part: the whole city flattens into the recycling bin in ten minutes. Take the photo first.