To innocent passersby, the annual DFL Cross-Dress Cyclocross series defies explanation: Without warning, 150 bicycle-mounted men and women, mostly in drag, emerge from a thicket in full sprint, leap from their cycles like acrobats, and then throw them over their shoulders and sprint up dirt embankments. This is a two-decades-old subterranean version of a century-old off-road sport called cyclocross. The San Francisco version, however, is even more anarchic. Events, which are held during September and October, are announced by word of mouth mere days before each event; entry fees are waived for cross-dressers, while people in gender-appropriate attire pay $5. Typical fields of 100-plus riders include national and world-class athletes. Courses are set up, raced upon, and abandoned without government permission in the spirit of anarchy that participants believe guides their sport.