What are the best Bay Area activities for toddlers on rainy days?

The Bay Area Discovery Museum has lots of indoor exhibits, including an "undersea" area, a train room, an art room, and a room devoted to traveling exhibits.

The Children's Discovery Museum is all indoors,but can get kind of chaotic.

Habitot in Berkeley is also indoors, but is very small and cramped. The best exhibits there are the ones for very small children, including a pre-walkers "garden" and a water play area.

The relocated Steinhart Aquarium is near Zeum and an indoor carousel-- very walkable if you've got a good umbrella. Also nearby is the Metreon where there are movie theaters, an arcade, and the excellent "Where the Wild Things Are".

how about going to the Gymboree- it is a great, safe place that have many activities among a child-safe inner door playground

you can also go to the aquarium in Monterey, it is an hour away but great fun for childern. there is a huge playroom there that have many activities about the sea world.