National Archives is an all around good resource for history teachers to have bookmarked. I've written about some of their services in the past (here and here) and today I'd like to point out a couple of their other offerings. The National Archives's YouTube channel offers twenty playlists of archival footage covering everything from the Great Depression to WWII to NASA's space exploration to the Olympics and much more. I've included a video of short film from 1935 documenting the work of the TVA.
For those of you who are fortunate enough to work in schools that are encouraging students to use their iPhones, iPads, and Android devices for learning, the National Archives has free apps you might want to consider using. The Today's Document mobile app from the US National Archives is an interactive gallery of 365 documents and images from the National Archives. These are the same documents and images that are included in the Today's Document RSS feed. With the mobile app you can select any day of the year to find out what significant things happened in US History on that day. You can also select "random" to have a random document or image appear. The mobile app provides the same background information that you can find online.