RepRap

Pottery and ceramics community. Techniques, glazes, and firing.

Wiki for appropriate technology and sustainability. DIY solutions for the world.

Global Investigative Journalism Network. Resources and training for journalists.

Roguelike development wiki. Game design, programming tutorials, and genre history.

Mountain encyclopedia and climbing routes. Peak info, trip reports, and photos.

American Radio Relay League. The national association for amateur radio in the US. News, licensing info, and technical resources.