Hot weather invariably leads to two things: piles of empty juice boxes and thoughts of water. This simple craft lets you combine the two, letting your young shipwrights head out to chart the depths of the backyard kiddie pool.
Cut a rectangular sail from the scrap plastic and decorate it with markers or stickers. Punch a hole at each end and thread the straw through the two holes.
With scissors or a craft knife (a parent's job), cut a small X in the center of the empty juice box and insert the straw and sail.
For a fun contest, hold a juice box regatta in a plastic swimming pool. Give each boatbuilder a straw, then have them line up their crafts and see who can blow her boat to the other side of the pool. Last one across gets the next round of juice!