The best stories for this event have a strong plot and dialogue. Something has to happen, and there needs to be a change. The more ready your story is, the more likely you are to get cast in the show. This is one of the only show we have with no theme, so it's a great chance to tell that story you've been wanting to tell.
Note that you will have limited creative say in the outcome of the film. You have to be ready to tell a story that you can let go of. You may our may not like how the film turns out, but if you go into it with the right attitude, it's fun to see how it's interpreted by the team. Chances are it will, almost always, be wildly different than you expected. Also note that most of these filmmakers are, to varying degrees, amateurs--still learning the craft of filmmaking. Plus, they are working with very small budgets.