**SIXTH IN A SERIES OF 12 STAND ALONE PHOTOS**Clown hopeful Andrew Liebman, 19, of New York city rides a unicycle during auditions for the Ringling Brothers Barnum and Bailey Circus Clown College at Madison Square Garden in New York, Monday, April 6, 2009. (AP Photo/Kathy Willens)
Packs of unicyclists will speed around downtown San Francisco Saturday morning, eager for glory.
The race is part of the North American Unicycling Championships and Convention, dubbed the "U Games," a weeklong series of events in the East Bay and San Francisco for single-wheeled enthusiasts of all ages and skill levels.
Saturday morning's event, billed on the California Unicycling Association's website as "The First Unicycle Criterium on the West Coast," will take place from 8:30 a.m. to 10:30 a.m. around a square block from Front Street to Union, Battery and Green streets and back.
The race features separate "fun" and "competitive" heats of six to eight laps each, with top riders reaching speeds of over 25 mph, the website says.
The block and surrounding streets will be closed to vehicle traffic during the event.
A unicycle "tour" of hilly San Francisco and the Golden Gate Bridge follows at 1 p.m.