I found the faces videos in the supplemental materials very amusing. They seem to be quite cartoonish, in the sense that they are very exaggerated expressions. I wonder how the classification algorithms would work with more subtle expressions of emotions, particularily eye-area movements.

It might be interesting to train and classify specific actors in movies or tv shows, maybe as a way to grade their performances in terms of 'range' of emotions. How varied are their emotions? Do they always get angry the same way or does it vary from scene to scene. Could be an interesting tool to train actors...