I got this through work, Trips for Kids takes inner city youth on weekday and weekend mountain biking trips usually at Phoneix Lake and China Camp (no backside ). They are need of volunteers and I have volunteered with them in the past, fun times!

Anyways thought I would pass this along to see if there is any interest

Volunteer to take inner city kids on day long mountain bike rides on Wednesdays, Thursdays, or weekends in Marin County. You will be one of several other volunteers along with one staff ride leader from our agency. You will be paired with 1 or 2 kids to accompany them during the ride and to ensure their safety. Our rides are a very popular volunteer activity and you are guaranteed to have a wonderful day and to bring much happiness to the kids on the trip. Must have your own mountain bike, be an experienced mountain bike rider and enjoy working with kids 10 - 17 years old

http://www.tripsforkids.org
(415) 458-2986