I agree with HUE, in small and snappy segments will prove very effective. If you are teaching kids then I suggest some Disney animation especially for the smaller children or go to
www.kidzclub.com (I think that's the right one) which has some short clips and tongue twisters. For kids I guess it's important not to show too much of a film in one go and not to stop the film every two minutes asking questions
Also for adults you can get the script I'm sure for pretty much any film or TV series so they can watch the show, read together with the script and try to understand it better. You could let them listen first and then give them the script or visa versa.
Best of luck!