In Boulder, there's an annual event called "The Kinetics" where teams create a craft that can be raced both on and around the local resevoir, over water, land, mud, and spectators. The week before, there's a parade in downtown Boulder where the teams can show off their works in progress. The costumes are fantastic and people gather around to watch and have a great time.
The best part? Trying to figure out if the crafts will float.