In this representation, I used "item" attribute links when linking to an individual movie from the larger movie list. I used "related" when linking from an individual movie back to the larger movie list. I've linked the movie resource to the show times resource using a "related" link as well. And again, when linking out of the showings resource, I use a "related" link.
I used the microdata data type, following data types found on www.schema.org . I used the following properties and types found on schema.org :
Title: Something to identify movies. Pairs with an id to make sure each entry is unique.
Description: a short description of movies
Duration: How long the movie lasts. Can also be thought of as runtime.
Rating: An MPAA rating, on a scale of G, PG, PG-13, R
Showing: What time(s) the movie will be shown.
Licence: Whether or not the theather has the licence to show something.