The Value of Unstructured Play Time for Kids - Pacific Standard: The Science of Society
This article talks about the value of unstructured play.
To clarify, we at Peaceful Playgrounds believe that play time should be unstructured. We believe that "enriching" the play environment and then allowing children to play without adult facilitation or intervention.
http://www.peacefulplaygrounds.com/product/catalog/peaceful-playgrounds-recess-kit/
Peaceful Playgrounds featured article on Unstructured vs Structured Play