This is a helpful cite for world history teachers specifically. It has some sample lessons as well as some additional resources for how to teach a world history class and help make it interesting.
This cite has complete lesson plans for various grades and subjects, but I think that Social Studies and Science will find it most helpful. There are also activities that the students can do at home or during class.
Websites for English, Math, and Finance purposes. Includes sites that specialize in tracking old math calculations, to citing sources, applications for calendars and homework dates which notify via e-mail or SMS. Sites to translate units as well as translate text and much more!