Toyon
http://en.wikipedia.org/wiki/Toyon
They claim that the Hills around Hollywood were named after the Toyon Bush/tree. In the 20's they were so popular that California passed a law forbidding the picking of the Christmas berries.
The picture posted of my bike and a toyon tree is along the 5 freeway and the Griffth Park bikeway. Most likely it was planted but along the whole path you will not find another.
I tasted the berry and it was a bit astringent and like an old apple where it starts to be starchy.