http://www.free.ed.gov/ As recommended by Bob Frank, Director, Communications and Technology, Center for Collaborative Education "The link...  takes you to one of the best comprehensive sites I’ve seen for high quality, diverse teaching materials and lesson plans, provided by the U.S. DOE. I spent some time on it, looking especially for problems of Eurocentricity in the various fields it covers (including math, social studies, music, art, languages...a whole lot). While some parts are more Eurocentric than others, wherever I looked it was possible to create a pretty diverse curriculum of very high quality..."