Under an exception in the Copyright Act, instructors may show a movie to students on the premises of the University for educational purposes. There is no requirement to report the movies you show.
Performing a film in public for other purposes requires permission from the rights-holder prior to the event. If you are uncertain in you need permission, contact the Copyright Office for assistance.
Below are links to some relevant resources.
Guide for Student Groups - Showing Movies on Campus
Film Studies - Videos (University of Alberta Libraries)