At first, we'd use it for a fort. After it got some wear and tear, we would flatten it out for a sled. We'd run and jump on the cardboard and slide down the leaf-covered hill, hopefully dodging the trees. After we tired of that, we would draw on it.
When Mother couldn't stand the sight of it littering her yard any more, and we'd burn it on the brush pile and toast marshmallows on wire coat hangers!
I don't think we missed a thing by not having iPads and smartphones!