The California State Parks are looking for volunteers! From their brochure:
In addition to ongoing opportunities in parks, one-day events are scheduled for Earth Day and Trail Days in the spring and Coastal Cleanup Day in the fall. These days offer great opportunities to spend time with your family or to make new friends as you get out and help make a difference. In many parks, annual and special events take place to celebrate our resources while teaching visitors about the wonders of nature and history. Join us—be part of what makes California so extraordinarily unique and wonderful!