And while the races are competitive, cyclocross is also beloved for its laid-back atmosphere and sense of humor. (Taking yourself too seriously is for road racers.) Joan Hanscom, the organizer of the Louisville event, recalled a recent cyclocross race in which a fan in a unicorn costume dangled cookies from a fishing line on the course for passing riders to grab.

WSJ: Cyclocross: The Other (Cooler) Super Bowl��Jason Gay