This 18-minute talk is by far the best explanation I've seen yet of why you should question copyright.
In the last few years, I've watched QCO Artist-in-Residence Nina Paley refine her message about the harm of copyright and permission culture. Now it's the most direct and most effective it's ever been. If you want just one video to show people to explain to them what this movement is about, let this be the one. Nina tells an appreciative audience why she had to set her mind free in order to make art, and shows some wonderful clips from her next film Seder-Masochism — a film that simply couldn't be made within the permission culture that Nina diagnoses so eloquently: