This Berkeley non-profit well reflects the value of its surrounding community. They work on projects that support sustainable agriculture in urban settings, such as farmer's markets, parks that incorporate working farms (such as Sunol Ag Park in Oakland) and educational programs informing the public of the importance of buying and eating food grown locally.
Though they do receive some governmental funding, they are reliant on donors, interns and volunteers to keep the program in operation. Go to their website to see how you can get involved.