Ambiguous Ending

Sometimes the resolution isn't clear-cut. There's a lot left unexplained and the audience is still asking questions.

Contrast Happy Ending and Downer Ending, where the conclusion is obvious.

Film - Live Action

 * Inception: Ends with Cobb returning home to his children after a successful heist. Just to be sure, he spins his totem top one more time, but runs off to see his kids before it stops. The screen cuts to black before the audience knows as well, leaving it up in the air if Cobb is still dreaming or not.