The Lake Oroville Bicyclists Organization presents 24-HOURS of GOLD in Lake Oroville State Recreation Area (Oroville, California) on November 15 & 16, 2008. The course is described as "Ten-mile course is fast and challenging! The ten-mile singletrack course twist and turns, climbs and drops through oaks and chaparral."
The entry fee is $100 per person (Limit four persons per team) and there is FREE Tent CAMPING to the first 100 to enter. You can signup at the active.com page for Lake Oroville 24 HOURS of GOLD.
Thanks to Rodney for the info on this.