If you don't mind the drive you can try Sycamore Canyon out in Thousand Oaks. It's a great ride with a variety of trails. Singletrack, switchbacks, a nice ridgline on "backbone" trail, to "hell hill" (1000 foot gain in about a mile, or at least that is what I am told). Most trails meet up down at the beach. Of course you ride down to the beach and then back up, about 20 miles round trip depending on the route.

It is at the top of Wendy drive off the 101 north, about an hour from Pasadena.