My 2 year-old really enjoys this park.
The park has a lot to offer: beautiful man-made lake with the fountains, geese and ducks swimming in the lake (we saw the otter family there the other day!!), another lake, which is more tranquil, well-sized playground, beautiful rose garden (frankly, I think it is more beautiful than the SF rose garden), and many theme gardens (smell, butterfly, etc). The parks also hosts festivals pretty frequently.
Overall, a beautiful park, especially on a beautiful (not too hot) day.
Splendid Olympic-sized pool, as well as a whole separate diving pool! Lap-swim/entrance fee is only $4 (CHEAP). Nice water temperature, always clean water, and a friendly atmosphere with very nice people.
Home to excellent swim teams (both USS and Masters' teams), in a really beautiful setting, this pool is a gem in Contra Costa County.
The only downside i would say is that they have open showers with luke-warm water in a locker-room that is in great need of updating.
For a few bucks a head and a tad of imagination you get access to what feels like a private pool on an off day. Meaning - great lawn area, uncrowded adult and kiddie pool and the hot Walnut Creek sunshine. My wife and I have gone here since our childless days and couldn't wait to bring our little guy there last summer. His opinion-squeals of delight. This summer will be even more fun now that he can walk. Oooh, bring on the sun.