In a view, how can I display all sub categories of a given taxonomy term with content from each sub category?
This isn't a great answer, but after a couple days of trying to do this myself, the best I could figure out was to use Views Field View (I think that Views Grouping Row Limit would probably work too, but it's still in dev).

Create a basic node view that lists off your five movie node titles (along with any other teaser-like content you'd like), set your page to limit to five entries, and set the contextual filter to the movie's taxonomy term.

Then, make a view that shows taxonomies belonging to the vocabulary (movies). Set the contextual filter to "taxonomy term: parent term"), and output the tid (hidden) and term title. That'll make a list of your parent terms, so now add a views_field_view (set it to use your first view for input, and the tid for your argument).

Again, there's got to be a better way than this, as I'm sure it's going to create some real system overhead.

Pleeeease, someone come up with a better answer!