[AtlasBarfed]

What you want is the manhattan model: a huge park surrounded by extremely high density residential towers. You'd have near-immediate access to needed free outdoor fields.

The manhattan model is so strikingly effective that the rich have basically monopolized it. What needs to happen in many urban areas is to replicate this. Of course that would mean huge numbers of buybacks of individually owned blocks of city, an almost impossibility in US legal system practically speaking, even with eminent domain.