Green hour

A Green Hour is time for unstructured play and interaction with the natural world. In 2007, the National Wildlife Federation launched GreenHour.org, an online resource providing parents the inspiration and tools to make the outdoors a part of daily life.

NWF recommends that parents give their kids a "Green Hour" every day.This can take place in a garden, a backyard, the park down the street, or any place that provides safe and accessible green spaces where children can learn and play. Scientific researchshows kids are happier and healthier when outdoor time is in better balance with indoor time.

http://www.nwf.org/Get-Outside/Be-Out-There/Why-Be-Out-There/What-is-a-Green-Hour.aspx