Appropedia
Appropedia is a wiki for all aspects of sustainable and appropriate technology, catering to developing countries needing improved health and better quality of life, as well as to wealthy communities needing to reduce their environmental impact - and also improve quality of life.
Topics covered include energy, permaculture, sustainable farming, livestock, sustainable transport, intentional communities, green computing, clean water, wastewater, sanitation, greywater, principles of international development, and more.