If you get the NickToons channel they show episodes with "Avatar Extras". Think VH1's Pop-Up video with info bubbles giving behind the scenes info about story development, pointing out links between episodes, recurring themes, etc. If you've seen the whole series it's worth checking these out.
Stephen Chow should have been the one to do a live action Airbender movie. Look at the trailer for Shaolin Soccer
. That's a far better model of what the movie should have looked like than that mess M. Night gave us.