Have you ever heard of these things?! They originated from a landscape architect observing that kids liked to play anywhere, but on the playgrounds he designed. From this experience he imagined "A junk playground in which children could create and shape, dream and imagine a reality." From this started the adventure playground movement. As stated on http://adventureplaygrounds.hampshire.edu, "At adventure playgrounds children get to play how they choose; they are not limited by fixed play equipment or by organized activities or games. Children are given the safety of an enclosed supervised environment. Playworkers are always present to mediate disputes between children and help them when necessary." The idea is kind of a make it your own, do it yourself space for kids to create, control, and evolve the space to be what they want it to be. Check out this adventure playground in Berkley, CA. http://www.ci.berkeley.ca.us/adventureplayground/ Some toys designed around this general concept: Rigamajig Imagination Playground I want to play!