Mix cornstarch and water together. Let toddlers play with it in a bucket or in bowls with cups and spoons. Make the goop thick or thin. Cut doors and windows in the box to make a playhouse. Toddlers can draw on it with crayons or paint it with water and big brushes or sponges.
Toddlers like to draw with short, fat, unwrapped crayons.
Toddlers also like to play house with dolls and housekeeping props such as plastic dishes and spoons. Most toddlers are just learning how to walk and run. Go for lots of walks but make sure you hold onto the toddlers hand. Let toddlers tear old wrapping paper. Then have them paste the pieces to make a collage.