This morning @ShellTerrell posted on Twitter a blog from James Hollis on Invention at Play. This site can be found within Smithsonian's History Explorer, which is a partner site of Thinkfinity. First, be sure to check out James Hollis' blog "Teachers Love SMART Boards". He has some great ideas for using SMART Boards and interactivities.
Invention at Play can be used on interactive white boards and on student computers. One of my favorites is Cloud Dreamer. Students can create their own cloud and then "see it in the sky" to see what it looks like. There is a site on Inventors' Stories where students can read about inventors of different subject areas. For example, under "Recognize the Unusual", inventors of post-it notes and cardiac pacemaker's are listed.
Just like with all of Thinkfinity's partner sites, History Explorer includes lesson plans, activities, interactives, media, museum artifacts, and a professional development tab. The professional development tab is for teachers to learn more about teaching with primary sources and tips on using History Explorer.
A sample lesson from History Explorer that I chose was for K-4 and is "A Letter to Abraham Lincoln Homepage". Within this lesson is the topic that is covered, vocabulary, national standards, and instructional strategy. Also under related resources are several web pages to be viewed. When you view "Our Story: Activities: A Letter to Abraham Lincoln", there is a timeline with the historic time period highlighted, and more activities to do in the classroom.
I highly recommend this site for all grade levels of history and social studies. By the way, all of the above sites are free to use.