Here are a few things a lot of ages will enjoy:
-Alcatraz Island (this one is a must. you MUST see it. I brought my 11 year old daughter with me and she LOVED it!)
-Fisherman's Wharf (there are many museums, restaurants, and shops to enjoy for all ages)
-Gheridhelli Chocolate Factory
-Cable Cars (the cable cars are a classic! You MUST go on this before leaving the Bay Area.
-Chinatown
-Shopping! You can never go wrong with shopping and it is also a great time-passer. (If you need one!)
Make sure you stay in a hotel with many accomidations (ex: pools and spa)
If you stay at the right place and pack the right things, your trip to the Bay area will be fantastic!