I just discovered the site snagfilms.com that let's you watch full-length documentary films for free.
They have a library of over 200 documentaries which you can browse by topic or by titles from A-Z. There is a widget for every film, which is what they consider to be snagging a film.
The first one I watched (and will now take off my NetFlix rental list) was SUPER SIZE ME. That's Morgan Spurlock's look at the American obesity epidemic. He interviews experts nationwide and then put himself on a “McDonald’s only” diet for thirty days straight. This is a Sundance award-winning feature that is entertaining, frightening and informative.
Not that this site is designed for educational media use (there are commercial breaks), but you could use that particular film to talk about corporate responsibility, nutritional education, health issues, school lunch programs and other issues.
You can also put films on the web. You can embed a widget on your web site, which they call "opening a virtual movie theater" and become a "Filmanthropist" (since you are donating your pixels and supporting independent films). When you click on "info" on any widget, you learn more about that film and a related charity you can also support.
I've been meaning to blog about documentaries for a while now but I haven't gotten the chance to commit the words to HTML. They don't make documentaries like they used to. The big budget ones still deliver, but ever since Behind The Music or E! True Hollywood Story, the "genre" has become over saturated with quickly churned out drivel. The Biography channel is a perfect example of this. They churn them out so quickly that they offer little insight and makes it not worth the time, even if you are interested in the subject matter.