Oakland Zoo, Oakland
The Oakland zoo is a nice afternoon for the kids. It's not San Diego, but some of the exhibits are very nicely done. Lots of giraffes, a close up view of elephants, some lions and tigers - all in a very nice setting.
Just outside the zoo entrance are some nice rides for the young kids - a buck or two per ride and a small scale train that circuits the zoo - very nice.
All things considered a pleasant afternoon - but definately a kids-oriented venue.