There are county-wide events that require citizen participation for success. Your efforts will have a beneficial impact on the environment and give you a sense of accomplishment for getting the work done!
Coast Clean-up Day - Yearly in September - http://www.coastal.ca.gov/publiced/ccd/ccd.html
Creek Clean-up Day - Starting 2011, will be same day as Coast Clean-up - http://www.creekday.org
Elfin Forest Clean-Up - For information, contact S.W.A.P. at P.O. Box 6442, Los Osos, CA 93412 or leave a message at: (805) 528-0392
Earth Day - Yearly in April - http://ww2.earthday.net/
Endangered Species Day - Third Friday in May, yearly - http://www.endangered.org/campaigns/endangered-species-day/
Eco Summit - Yearly in December, but check ECOSLO site for the date - http://www.ecoslo.org/