Documentaries are visual and aural productions of students' historical research, analysis, and interpretation which have a narrative structure and are created and presented on DVDs.
More tips from National History Day: http://www.nhd.org/CategoryDocumentary.htm
NOTE: The best final format for a documentary is a MP4, AVI, or WMV file, published and burned to a DVD. Due to multiple standards for DVD players, DVDs do not play on all devices; therefore, students should test their DVD on a number of players or bring their own laptop to the competition. Multiple entries from the same school should not share presentation equipment, as entries may be assigned at concurrent times. Internet access is generally not available at the competitions, so do not plan to present your documentary from YouTube or other online storage.
Check out even more examples from the National History Day: https://www.nhd.org/categories.
The National History Day now offers Google Hangouts for each project category during the contest season. Students and teachers may join in or listen to previous hangouts at: https://www.youtube.com/user/NHDHangouts/videos.