Take a classic movie (or heck any movie you like), and rescript the audio of a key scene. You will want to re-write the lines to change the meaning or intent of the scene, delete the original audio, and record your own (this can be done many ways, voiceover in iMovie, recording the audio and editing the track in any other movie editor).
For my example, I took Howard Beale's on camera rampage from "Network", and changed it to a diatribe on being bored in school., _cpzh4: Video, _cre1l: http://www.youtube.com/watch?v=fZcMucXO7es, _chk2m: Alan Levine, _ciyn3: 131, _ckd7g: VideoAssignments131, _clrrx: VideoAssignments, _cztg3: VideoTutorials131