Fourth of July Crafts for Kids: Flour Lawn Stars. Cut out star stencil, sprinkle grass with water (to make the flour stick) and then sprinkle with flour. This idea also works for Canada's July Birthday. Just substitute the star for a Maple Leaf.
Balloon Dart Board I say, let the kids blow up the balloons and you staple them to the board! For a party, you could fill each balloon with a number that wins a corresponding prize. Just pick out balloon colors that match the holiday or party theme.