You do not want to miss Yosemite. Make reservations to stay at least one night in the park. This is the most beautiful place. Check out this site for more info:http://www.nps.gov/yose/
I would also suggest exploring California’s Central Coast area. You will find small beach towns, coastal sand dunes, Monterey Bay Aquarium, Hearst Caste, wineries, and more.. It’s a blast to rent an ATV or take a hummer ride through the sand dunes at Oceano. Here’s a link about Oceano:http://www.cheers2wine.com/Oceano-Dunes.… The beaches along the Central Coast are not as crowded as in Southern California.
San Diego is a great place to visit as well. It’s known for its mild year round weather and there are lots of fun outdoor things to do. One of my favorite is kayaking through the caves in La Jolla. You see all kinds of marine life up close and personal. They also have jet skiing in the bay, hang gliding off the ocean cliffs, parasailing, hiking, biking, beach volleyball, a great zoo, and lots of museums. Learn more about San Diego at http://www.sandiego-romantics.com.

Yosemitie (roughly a four hour drive from the bay area) is well worth visiting.
Driving down the coast to LA is also a very beautiful experience and there’s a lot of stuff to do along the way (Santa Cruz, Monterey and the aquarium there, Big Sur, Hearst Castle, Santa Barbara, etc)
There’s also plenty to do in the Bay Area proper, Alcatraz, visiting Golden Gate Park, riding cable cars, etc. You might check out a Lonely Planet guide the next time you’re in a bookstore.

Yosemite was my first thought too!! It is beautiful and fairly cool in the summer and there is SO much to see!!
Also, my family got stuck in San Fran for a week with no car. We saw everything by foot or trolley and had so much fun. See Fisherman’s Wharf, Seal Rock, Coit Tower, China Town. There are a ton of little shops that carry these charm bracelets with charms representing all the cool stuff in San Fran. My sis and I each bought one and made sure to visit every place on it!! Oh, the Prisidio is nice too and there are a lot of museums!! You could go and visit UC Berkley across the bay!! There is a million things to see in the Bay area!!

Are you a water person? You could visit a nearby beach. Unlike Florida though, the water is very very cold here. You could also head south to Hollywood (or as I call it “Hollyweird”). If for nothing else, you can see unique people walking around.

Several things come to mind. A trip down the coast being one – if you take Highway 1 down the coast, you’ll see some beautiful vistas, and you can stop at Santa Cruz (great little California beach town), Monterey (charming, historic), Carmel-by-the-Sea (VERY charming, shopping), and Big Sur (gorgeous views, beaches, redwoods, rivers, little teeny towns with cute shops). To do all that, you’d probably need to spend a night or two along the way, but it would be a great trip!
You can take a ferry across the Bay & visit Sausalito (that would only require an afternoon). If you want to continue in that direction, you could follow Highway 1 north to Point Reyes Lighthouse, then on up to Mendocino and Fort Bragg, with stops along the way at some of the little towns and villages. Another gorgeous drive with plenty to see and do at the other end – and another “stay a night or two” for this one.
For things to do in San Francisco – the main attractions that EVERYONE should see at least once are: Golden Gate Bridge, Alcatraz, Cable Cars, Fisherman’s Wharf, Chinatown, Coit Tower, Union Square, and Union Street. And there’s more where that came from at http://www.discovernortherncalifornia.co…
Another trip for a night or two would be to Yosemite National Park – absolutely AWESOME and worth the trip, although the Valley Floor will likely be quite crowded in July or August.
Hope this helps & that you all have a wonderful vacation, whatever you decide to do!