Los Olivos Park is great, they have two playgrounds- one for the older kids and another for the younger. The restroom is located close to the playground (thank the playground Gods) and there are two volleyball courts not far from there.
The park is full of olive trees and it has a pretty awesome disk golf course. In the evening it is lit and there is always someone utilizing the different aspects of the park. The only thing it is missing is a splashpad and maybe a little more shade for the swings.