'Spartan' Film List
You don't know what Spartan films are? MADNESS!
These are films which essentially are one-act plays. They take place in limited locations (often only one), over a short period of time (often real time) with few characters and generally rely on only dialog to tell the story, rather than traditional action. It's minimalist film making at its finest.
Know of any others? Suggest them here in the comments!
Special mention to the HBO television series "In Treatment" which falls into this same category.