Some really nice drives around there. Epic scenery. If you like golf, there's lot of options. Painfully expensive.
Cold water beaches couldn't be more different than here.
The motorcycling around there is some of the best in the world, but technical.
You're fairly near the Bay Area (San Fran, Oakland, San Jose, Napa, Berkeley). Avoid those places except my outskirts of Napa wine country.
You'll also be right over the hill from silicon valley. Right across bay from Santa Cruz.
If you get a day or two off, go to Yosemite Valley. See El Capitan and Half Dome. Check out Glacier point there. Go during the week! Unless you have a fetish for Asian tourists. Also KIngs Canyon and Sequoia Park if you want to see giant redwoods. To get to these place you will cross the central valley which is interesting. Huge farms for miles.
Really too much to list as within an hour or two there is a ton of stuff to see and do.
edit: Definitely check out the Aquarium. They have a million gallon tank I believe. Full of giant tuna. Also had great whites in there. Saw one nab a tuna!
Dang, Chuckman pretty much covered it haha