If boredom's got your kids walking the plank, let them turn a refrigerator box on its side and set sail on the waves of their imagination.
Fishing trip: Bring a tackle box and wooden dowel fishing rods, construction paper fish, and worms!
Pirate ship: Grab bandannas, a stuffed parrot, eye patches, broom oars, and a map leading to secret treasure in the backyard.
Racing speedboat: Put on bathing suits, life jackets, and goggles, then rev the engine and hold on tight.
Spread out the tarp and set the box on it, on its side, underneath a clothesline. Open up -- or cut away -- the top of the box (parents can use a utility knife).
Paint waves on the boat. Once the paint is dry, clip a sheet sail to the line, assemble some themed props, and it's anchors away!