Happiness is a simple box.
We had take out from one of our favorite BBQ places and the food was packed neatly in this white box. The box was on it's way to the trash until the boys saw it. They played and played in the box. They would put toys in it or they would get in it! You can see a room full of toys behind the box, but they chose the box over the toys. It provided hours of entertainment (until I finally was able to sneak it to the trash).