Hit and Run 5K, Nashville

Here are the sounds you'll hear at a typical marathon: huff, puff, wheeze, snort, repeat. Here are the sounds you'll hear at the Hit and Run 5K: sploosh, boing, splat, whoopee, and other onomatopoeias that haven't yet been invented. Less like a race and more like running through a living cartoon, the Hit and Run 5K's obstacle course of inflatable onslaughts has been known to "make ninjas cry."

Dodging, ducking, leaping, and balancing across a wet-and-rubbery battlefield, contestants face formidable foes such as the giant spinning balls of the Duck or Dive, the unreliable puffy poles of the Wobble Walk, the flying wet menaces at the Whacking Wall, and the Bouncy Bridge, which is kind of like London's Tower Bridge if it were any fun. All contestants receive their own spiffy T-shirts and matching headbands—a fetching ensemble that instantly deflates roving dodge balls—along with a hearty packet of deals from the race's sponsors.