Turn kids loose with sand, water, and simple stuff they can move around—and then get out of their way. In no time, they’ll create their own world of castles, fanciful creatures, and vehicles powered by sheer imagination.

Such childish fun may seem out-of-date to today’s heavily scheduled kids and their wellmeaning parents. But free play is about to get a big boost. Imagination Playground, designed pro bono by architect David Rockwell in collaboration with the New York City Department of Parks & Recreation, is under construction in lower Manhattan.

When the playground opens next year, it will showcase a multilevel environment designed to let kids act like kids. Four years in the planning, the playground will come with trained “play associates.” Their charge: encourage youthful creativity while reminding parents and nannies to take a giant step back.

Now, a new partnership between the Rockwell Group and KaBOOM!, a nonprofit that helps communities build playgrounds, is preparing to take the essential ingredients of the Imagination Playground to a much bigger scale.

The two organizations have formed a for-profit venture that will handle distribution and marketing of Imagination Playground in a Box. The basic product is a container on wheels, not unlike a magician’s box, that comes stocked with kid-friendly building materials. These gears, blocks, and giant noodles are made of weatherproof, environmentally friendly foam.

“We want to make these ideas mobile and portable,” explains Darell Hammond, KaBOOM! founder and CEO. He envisions kits going into back yards, community centers, housing projects, schools, or any other space big enough for kids to congregate. The idea isn’t to replace traditional playgrounds but to complement them. “We want to create better play experiences,” Hammond says, by encouraging “creativity and unstructured, child-directed play.”

“Our idea of Imagination Playground was never as a one-site project,” Rockwell adds, but rather the launch of a larger play initiative. “When KaBOOM! approached us because of their interest in this innovative and transformative perspective on play, it seemed like a really natural and perfect partnership.”

KaBOOM! has managed to change the game when it comes to how playgrounds get built. Since the organization was founded 14 years ago, the percentage of playgrounds built by community volunteers has mushroomed from 1 percent to 40 percent. KaBOOM! is the nation’s leading purchaser of playground equipment, which gives it a voice about what gets built. The group is also adept at recruiting business partners to help fund and construct the playgrounds.

Initially, KaBOOM! planned to seek foundation support to fund the rollout of Imagination Playground in a Box. When the economy took a dive and grant funding evaporated, Hammond says, setting up a for-profit company “seemed to be the fastest way to bring the product to market while letting us control quality and keep the price down.”

Read more stories by Suzie Boss.