Personally, The Rocky Horror Picture Show.
I knew it was going to be quite the experience before I went for the first time‡ but it was so much fun I had to keep going back bringing friends each time.
It’s still a fun tradition to do though we haven’t done it since last year, we’re probably going to try and go again in a few weeks.
‡ I had seen it many times before going to see it in theaters for the first time.
When I was a kid, Nightmare Before Christmas. Must’ve convinced my parents to take me to see it at least eight times. I’ve watched it at least once every year since then, and it stayed my favorite movie for most of my life, until Everything Everywhere All at Once finally usurped it almost 30 years later. Saw that in theaters four times.
Oh, and Lord of the Rings. Saw all three in theaters at least three times each. And, for some reason, Superbad. Went to five showings of that.