Youtube isn't just about sharing videos.. You can create them online as well. This page has links to some integrated web app tools for creating and editing videos and animations online.
So, say for example, I want my kids to come up with videos for Act 1, Scene 1 of "Macbeth", I can have them come here and create some great summaries, demonstrating their understanding and building upon the nuances of Shakespeare.
By the end of the play, I could have lots of animated "Macbeth"s! Awesome!
Via Richard Schwarz