re: San Francisco with Kids

How old are the kids? I'm guessing young, considering your interest in the exploratorium.

All ideas listed here are great. Has walking across the Golden Gate bridge been mentioned? That's about the only other activity with kids not already mentioned.

Oh here's a tip, if you take cable cars from market. Instead of waiting over an hour in line, walk a block down and just hop on at the first stop. They purposely one half-fill those cars for people getting on down the line. One block down you can just jump right on, might not get the best seats though.

Muir woods
Ferry landing
Golden gate park
Walk across the golden gate bridge