The Open Education movement has been a powerful way for teachers to take content into their own hands, compiling and repackaging lessons that suit their individual classrooms and learning goals. There are lots of great Open Education Resources (OER) available online for educators to use. Edutopia has put together a nice guide to some of the best free sites and has included ideas on how to turn the information into lessons and textbooks.
Check out MindShift's list of Open Education Resources and ideas for using them too.