Is that event cinemas by any chance? I think I am aware of those. The sessions basically have the sound down and the lights are half dimmed as well as some space for parents to feed/change bubs if they need it.
Our awesome Cinema Pub has something like that, they call them Sensory Sensitive Showings, and lights are not totally off, sound is lower - they say it's especially good for autistic kids and some other disabilities. They don't show ads or previews, just the main feature, and it's ok to stand up and walk around, or make noise. They even encourage anyone with any dietary restrictions to bring their own snacks in if they want.