Spinoza

I've been listening to The Teaching Company's Great Minds of the Western Intellectual Tradition on the way to work again. Yeah, I know it sounds kind of dry. Sometimes it is, but usually its really interesting, and it makes 45 minutes go by faster than any DJ's can manage it.

So, I think I'm interested in Spinoza. I hear he's near-impenetrable, though. Does anyone know anything about him? Have any feelings, or recommendations on where to start?