Shirin (2008) is an Iranian film directed by Abbas Kiarostami. It's truly unique.
We watch an audience of women who are watching a movie about Khosrow and Shirin. That's the title of a famous tragic romance by the Persian poet Nizami Ganjavi (1141-1209). It's a famous poem in Iran. (There's a whole world out there of things that I don't know.)
In any case, the women are watching a movie. We can hear the music, the sound effects, and the dialog. But we never see the movie!
What we see are women's reactions to what they are seeing on the screen. When I looked into it, it turns out that Kiarostami filmed over 100 women. All of them were famous Iranian actors or other cinema professionals.
For example, one of the women was Leila Hatami, who later starred in the film A Separation (2011). I believe all of the women were Iranian except for one. She's a famous French actor who had worked with Kiarostami in 2010. If you watch carefully, you'll recognize her.
This movie has an anemic IMDb rating of 6.7. (I guess that you either buy into the concept, or you don't.) I thought it was much better than that, and rated it 8.
P.S. We viewed this film on a Cinema Guild DVD. It came with several extras, one of which is worth seeing--Taste of Shirin (2008).