Check out this mid-valley ride on Aug 15 in the foothills of the coast range. The ride returns this year after a gap in 2008. They have now added a century option to what was the Alpine Half Century in 2006 and 2007. I rode it in 2007 and it is a very scenic route. There were only 60 registrants that year. It also has more challenging hills than the typical organized event ride in the valley (like Monster Cookie, Peach of a Century, Covered Bridge Tour etc.).
http://www.alpinecommunity.net/pg23.cfm