I thought this could be a fun thread since we're always looking for a couple movies to watch on a Saturday night.
What are you favourite "double bill" movies? Movies that work together but aren't related to each other. So no sequels, remakes, etc.
Here are a couple to get started. I added a third to make it a triple feature.
Close Encounters of the Third Kind and Arrival
Triple Feature Bonus: Contact
Face/Off and Con Air
Triple Feature Bonus: The Rock