The Canadian National Film Board (NFB) is a great repository of all sorts of films and documentaries. They have an extensive collection of films and archival footage related to both world wars that are pretty interesting in themselves. What will really be of interest to users of this forum, though is a 7 minute archive of WWI aviation footage (optimistically) titled "Airplane Casualties". Lots of really interesting footage of all sorts of string bags. They've got a free iPad app, too.
Not just one for the Canucks of the forum?
http://www.nfb.ca/Enjoy,
Lindsay