The Color Fight, Nashville

There's just one rule at The Color Fight, a 5K run that benefits local charities and nonprofit organizations: participants must wear white. That's because white fabric is ideal for showcasing the colorful powders—made from biodegradable food-grade starch—that runners jog through at each kilometer of the event. The powders fill the air like brilliant clouds, covering joggers head-to-toe in a rainbow of hues. At the end of the 3.1-mile event, which has no official winners or finish time, participants can toss handfuls of powder through the air in a playful color-fight.