You can browse by grade level or by subject. Both World and American topics. Has a this day in history spot. Also tons of speeches to listen to. Check here for Black History month activities.
Every country is listed here alphabetically.
Then, each state has other links to more information. Also a neat question and answer page filled with interesting facts. The main page page is cool enough, but dig down deep enough to the classroom ideas and find lessons plans and printable worksheets to teach geography and culture. The letters from the field section contain some interesting insights. This is an interactive site for k-12 classrooms that follows expeditions to meet people in other countries and learn about their cultures.