International

IPA Promoting the child's right to play http://www.ipaworld.org
Study of adventure playgrounds and city farms in Europe and what they contribute to sustainable urban development http://www.bdja.org/ oli/ index.html
Lectures and documentation from the conference: Adventure playgrounds and City Farms for the 21st Century [Berlin 1999] http://www.bdja.org/ anima.htm

Canada

Canada's Office of Urban Agriculture: Rediscovering the Animation Playground http://www.cityfarmer.org/ AnimationPlayground.html

Germany

AKiB A federation of adventure playgrounds and children's farms in Berlin http://www.akib.de/ english/ english.htm
BDJA Association of adventure playgrounds and city farms in Germany http://www.bdja.org/ english.htm

Japan

IPA Japan Japan's international play association http://www.ipa-japan.org

Switzerland

Speux Speux is the union of adventure playgrounds and children's programs. http://www.speux.ch
Robi-Spiel Aktionen A Swiss organization of adventure playgrounds in Basel http://www.robi-spiel-aktionen.ch

United Kingdom

Kidsactive (formerly HAPA: Handicapped Adventure Playground Association) http://www.kidsactive.org.uk/
London Play "for every child in London to have high-quality, accessible, and inclusive play opportunities." http://www.londonplay.org.uk
Playlink Playlink supports local groups in creating play opportunities for young people. http://www.playlink.org.uk/
Fairplay Promoting the child's right to play http://www.arunet.co.uk/ fairplay/ home.htm

United States

Projects for Public Spaces Dedicated to creating and sustaining public places that build communities http://www.pps.org
Children's Environments Research Group Provides a link between research and design, policy, and programs that improve environments for children http://web.gc.cuny.edu/ che/ cerg/
Natural Learning Initiative Promotes the importance of the natural environments for children http://www.naturalearning.org
Adventure Playground in Berkeley, California Open year-round http://www.ci.berkeley.ca.us/ marina/ marinaexp/ adventplgd.html
Adventure Playground in Huntington Beach, California Open summers http://www.ci.huntington-beach.ca.us/ CityDepartments/ comm_services/facilities/ Huntington_Central_Park/ Adventure_Playground.cfm
Adventure Playground in Irvine, California Open year-round http://www.ci.irvine.ca.us/ depts/ cs/ commparks/ specialfac/ adventure_playground.asp