When it comes to one-horse advocates who also run nonprofit organizations on a shoestring, my vote goes to Bob Banner of http://HopeDance.org.
Ive known Bob for more than 10 years, and hes responsible for impacting thousands of local residents by advocating for sustainability, green energy, conscious lifestyles and other issues and concerns in the county through his publications, films and website.
Best known for his bimonthly periodical Hope-Dance, which was published free (and which I contributed to regularly) for many years, he now traverses this and other nearby counties presenting indie films, mostly documentaries, on all manner of important (though sometimes esoteric) subjects. Recently he has presented videos on the Dalai Lama, housing alternatives , the value of laughter and water conservation and consciousness.
He will be presenting a program with the film Last Call at the Oasis in Cambria April 30, with my participation as a rainwater harvesting resource person. I urge you to stay abreast of Bobs activities (he publishes an online calendar on his site, which includes related events). But if you cant come to Cambria, hes in nearly every SLO County community at least once every one to two months.