Does your town have a neighborhood 4th of July bike parade? I've been to neighborhood bike parades in several towns and they are such a fun way to celebrate! If your town doesn't sponsor one, it would still be fun to gather the neighborhood kids, help them to decorate their wagons and bicycles, and cruise around the neighborhood.
Martha Stewart has tons of great ideas for decorating bicycles (of course she does!), including some festive printables.
(Photo from: Martha Stewart.com)