Playgrounds with spaces that attract children increase the likelihood children will use them, the authors note, and playgrounds offer an opportunity for children to experience the risks of outdoor play. The authors used natural observation to study the children at play in a newly built New Zealand playground where such an important kind of behavioral learning was possible. In five-minute intervals over 615 minutes, they observed children of various ages and genders using the playground equipment. They discovered that swinging, spinning, and climbing--all at speeds and heights that made them risky--were the most popular activities overall for children. They discuss the important implications of these and their other findings for playground designers and for those worried about the decreasing time children spend playing outdoors.