Depends the time of year and age of kids. If in winter, Yerba Buena square has a carousel, ice skating etc great for kids. The Exploratorium, a walk across the Golden Gate Bridge and if time hopping over to te Marin Mammal Center is also entertaining for all ages. Can't fail with a ferry ride to Alcatraz either.
30s somethings: enjoy Zuni, SaltHouse, Nopa, Nopalito, Anchor & Hope, cotogna, wayfarer tavern, Perbacco. Lots of restaurants on Valencia street between 17th & 22nd. about 9 years ago