Students or student clubs often wonder, "is it okay to show a movie?"
There are two primary contexts in which you could show a movie without public performance rights, which is basically the license that allows you to show a movie legally in public when you are not the copyright owner.
1) In your private home (as long as you're not opening it to the general public or charging admission).
2) In a classroom as part of a class.
For virtually all other showings you will need to have public performance rights in order to show a movie.