Infrastructure is defined by the American Heritage Dictionary as “an underlying base or foundation for an organization or system.” When you think about urban infrastructure, what comes to mind? Electrical grids, water and sewer pipes, roads and train tracks are obvious answers. Americans tend to have a very utilitarian view of infrastructure, and things like museums, schools, and parks aren’t seen as infrastructural because their outputs are less tangible. But make no mistake about it: Schools and parks are just as important to modern cities as are roads and pipes; they just direct and manipulate very different resources.

If it’s true that one of the contemporary city’s greatest resources is its human talent pool, then it makes sense for cities to invest in strengthening that resource once basic needs (electricity, water, etc.) are taken care of. Certainly urban education systems are high on the list of priorities here, but the case has been made many times for the equal importance of after school programming for children, especially those with working parents. Voices from the medical establishment to the national newsmedia have covered the importance of play in recent years, and awareness of the long-term developmental benefits of creative, open-ended fun on developing brains is being quickly absorbed into the general public consciousness.

It makes sense, then, for urban designers and planners to consider play as a conduit in the system of places that develop a city’s talent pool. Things like playgrounds, sports facilities and the like should be arranged in a manner where safe, engaging facilities are available to all children — which is often not the case in our cities.

Promisingly, playspace advocacy group KaBOOM, creators of the Playful City USA program, recently launched a campaign called 100,000 Playspaces in 100 Days through which Dancing With the Stars winner Julianne Hough will donate a dollar to children’s charities for every play place in the United States marked by users on a map, up to $100,000. The end result will be a comprehensive map of places designated for play in cities and towns across America, giving planners and the growing ranks of their DIY counterparts a valuable tool for improving local play networks.

Of course, the mapping campaign only takes into account the sanctioned play areas in a city, with categories for playgrounds, ice rinks, skateparks, swimming pools, and play fields for baseball, football, soccer, and basketball. As every city-dweller knows, these places are important, but kids will play anywhere and everywhere. If a skatepark or playground is not provided, benches and planters will often suffice. The same can be said of streets and open lots standing in for absent sports fields. While the KaBOOM map will undoubtedly be a useful resource, the line between formal and informal play places is often more subtle than this mapping project can account for.

Open-ended play is where imagination and creativity are developed. Less formally-programmed play places offer a possible alternative to brightly painted playsets with their straightforward slides and tire swings, and should be considered when filling in holes in a city’s system of play places. Down under in South Melbourne, Australia, Phooey Architects recently created an open-ended play structure out of shipping containers (a much less cloying use for the things than the endless housing reuse proposals that have been suggested). The structure’s success is in its simplicity; the flexible play area can be used in as many ways as children can figure out to make use of it.

Americans who are interested in improving the more playful aspects of their cities’ infrastructure in the future will need to think beyond the monkey bars. Almost any public space can be programmed for play, and as Phooey Architects has illustrated, it doesn’t take a lot of money to create an exciting place for kids to exercise their imaginations. In fact, it just requires adults to exercise their own.

Brendan Crain is the founder of Where.