On top of the Moscone Convention Center in San Francisco is the Yerba Buena Rooftop Playground. Most of this playground is a giant rubber pit, great for bouncing, but that's only one of the many things that make this playground cool. The rooftop playground also has 25-foot tube slide (for tunneling or sliding, whatever mood strikes you), a play circle with a xylophone, a labyrinth of hedges (child-sized) as well as sand and water elements.
And when you've worn out the playground itself, move on to the butterfly garden, the 1906 carousel, the bowling alley, the NHL-sized ice-skating rink or the Zeum arts and technology center, a hands-on museum especially for kids. And it's all located in the middle of the beautiful Yerba Buena Gardens.