U.S. Government Resources
Kids.gov offers some short videos
http://philosophyslam.org "Philosopher of the Week." Scroll to the bottom of that page, and you will see a list of philosphers they've written about.
wikipedia.org: a great resource for many topics, but be sure to look at other sources to verify its accuracy. As a 'wiki' it is created by the public.
biography.com : a great resource to help verify wiki. Their biographies are broken down into short, mid-length, and detailed. A great concept.
13 Colonies - an interactive map game.
Here's a good British Broadcasting Company report on Native Americans expressing their view on a proposed oil pipeline that runs across sacred land. Concepts: Freedom of Speech; Right to Assemble; Land Ownership.