2008 Bear Valley Grizzly Challenge

This is a bit off the beaten path, but looks like it could be a lot of fun:

Saturday August 16th, 2008 delivers the "Grizzly Challenge" with steep climbs, pine forests trails and fast single track. It's a challenging course that will test your riding skill and fitness. Riders choose between 1 to 3 laps and cash prizes will be awarded to top finishers. Afterwards you can enjoy other festival happenings, join an afternoon ride, or simply chill-out. Then at the end of the day everybody is invited to join the festival barbeque dinner for a tasty meal, awards and good times.
Via Bear Valley Adventure Sport Festival website.

It looks like the XC race of 8.75 mile laps with ~1500' climbing per lap. Registration is $15 - $30 depending on category and there are payouts for podium finishes. Course map and elevation profiles are posted here.

There is also a host of other sporting events like kayaking, rock climbing and road cycling on tap for the Festival that runs all weekend.

And for those of you wondering -- Bear Valley Mountain Resort is located about 25 miles northeast of Arnold, CA.