More context on how to answer this: "Going to clarify what I mean by flex here: it's not a flex if you saw a huge bit movie everybody else also saw. It's gotta be a little bit cool, like a cult classic in first run or something that was yanked out of theaters really fast."

I'd say my most brag-worthy one was Cabin Boy, with Chris Elliott. Opening weekend, and the theater was me, my buddy Paul, and a third guy who was probably a theater employee making sure that two teenage boys didn't get up to shenanigans in an empty theater. Based on its box office, we may have been the only three people in America to see it.

Best one was probably Batman Mask of the Phantasm, one of the best Batman movies, also with Paul, also in an otherwise nearly empty theater.

The first date I ever went on was to see Cry-Baby (1990).

Sometime in late 1998 or very early 1999, as a senior in high school, I took my younger brother to see Rushmore in an empty theater in Savannah, Georgia. No one I knew had heard of Rushmore, so seeing it at all was already a special moment. But then to see it at, essentially, a private screening made life-changing. For a while afterwards, it felt like Rushmore only existed for my brother and me.

Donnie Darko was possibly the first R-rated movie I didn't have to sneak in to. We went based solely on the poster, not knowing a thing about it, and I've been listening to Tears for Fears and Echo and the Bunnymen ever since.

The cult for this movie is basically only sex and gender academics of a certain age and Tilda Swinton completionists, but: Female Perversions, May 1997, an near-empty theater in Edinburgh, Scotland.

I saw City of God in a small art house theater

Howard the Duck.

Your sympathies are welcome, and much appreciated

One of my earliest movie memories is seeing the original run of Saturday Night Fever with my mom and grandmother. I was four. I remember the scene where the one kid falls/jumps off the bridge. I had zero idea what was happening in the movie. Apparently I enjoyed it so much that my parents got me the record version of the soundtrack. I wore it out and my uncle got me another copy for Xmas a year or so later.

Cronos. Feels like there should be more, since all I did between 1994 - 2000 was go to movies or shows. Lucky me.

I saw Kids when it came out, on a date. No idea which one of us selected that one.

Crash (the Cronenberg one) I saw in a, thankfully, empty theatre. I think that was also a date. (Different guy.)

I guess I was lucky to live somewhere with a good selection of indie movies in the '90s because I also saw Iron Giant, Fargo, Magnolia, and Run Lola Run in local theaters.

We all missed it in theaters, but in like early 1996 when The Usual Suspects came out on VHS I was working in an indie video store. My friend Adam came in and rented it, and two hours later the store phone rang and he told me to come straight to his house after work because I needed to see it for myself. When it ended we called another friend and had him come over so HE could watch it. This is a very 1996 story.

Watching Memoria (2021) by Apichatpoing Weerasethakul in Grand Rapids during its initial run of touring, city-by-city screenings. The subtitles weren't working correctly, though we didn't know this until near the end of the film. The film is set in Colombia, and Tilda Swinton's character grapples with locating the source of a mysterious boom she keeps hearing. Only occasional lines of translated Spanish dialogue would appear on the screen. I thought we as the audience were meant to be thrown into a zone between languages and set adrift on waves of memory. An unforgettable experience.

Reservoir Dogs, Man Bites Dog, Meet the Feebles, Naked Lunch are the first that spring to mind. Like I'd imagine many here, I was a film nerd in my late-teens and would spend a lot of time at the multiplex/arthouse.

Ooh, and I saw Akira on it's first showing in the UK. Part of this run. It was a double bill with Tetsuo: The Iron Man, which would be flex if we'd gone to see it on purpose.

My friends and I, age 14 or so, sat through three showings of Napoleon Dynamite in an otherwise empty theater. Before we could stream things online, that was how we learned all the lines and constantly repeated them in class.

I saw Parasite 3D (Demi Moore's first starring role!) and Dawn of the Dead (1978) in theaters. For my first date with my wife, we saw Wings of Desire (1987).

Seeing Repo Man in the theater when it first came out was an absolutely transformative experience for me as a teenager. A couple years later a friend and I were lucky enough to see Harry Dean Stanton sing at a small local bar (the Cabooze in Minneapolis). He seemed very much like he was as Travis in Paris, Texas. He sang in Spanish beautifully. From the stage he asked for a tequila with grapefruit juice, which I thought was so cool I adopted it as my own favorite drink. Anyway, between sets my friend ran out to his car and got the tree-shaped air freshener and we cornered him for an autograph. He chuckled and said "Repo Man fans, eh?" and happily signed it.

A Japanese movie called ‘PornoStar’ (not a porn movie, https://www.imdb.com/title/tt0166314/) and another one called ‘Sleeping Man’ (https://www.imdb.com/title/tt0117161/).

Saw both at the Berlinale film festival. First one is a psychotic violence fantasy; the second one is so moving (soundtrack, actors, pace, imagery, everything), it makes me cry when I watch it.

Bonus obscure movie: Gummo (https://www.imdb.com/title/tt0119237/), directed by Harmony Korine.

My husband and I also lived near an art film theater in the late 80s, so we saw My Life as a Dog, I've Heard the Mermaids Singing, and Wings of Desire. Later on, we saw Run Lola Run, Hero, and Big Night and loved them all. Couldn't stay up until midnight discussing them with our friends, since nobody else saw them!

Blair Witch Project. The theater was empty except for me and two friends.

I didn't know anything about it except that there was internet buzz in 1999.

That was terrifying.

Not a cult movie, but a fun story I never get to tell. I'm 7 years old, and we're waiting in a line waaaay around the block to get in for E.T. at the Cinerama Dome. There's a lot of whispering among the grown-ups. I don't understand why. Then someone comes up and talks to a pretty woman behind us in line. I remember her saying "no thank you" before the person took her and her friends out of line toward the theater. I thought she was in trouble, so I asked my mom what happened. She said an actress was waiting in line to watch the movie, and they invited her inside. I didn't know at the time, but it was Jamie Lee Curtis.

I had a high school friend who is now a film professor and picked lots of memorable stuff; Pi (1998) is probably the best ratio of low box office to eventual prestige, but Run Lola Run, Buffalo 66, The Opposite of Sex, Rushmore all stand out.

Not the question, but I saw The Matrix and Fight Club on their opening days without knowing ~anything about them, The Matrix in particular we went to expecting to laugh at it. Grateful for getting to see those with zero expectations.

In high school, I won my only radio call in prize, free passes to an advanced screening of John Carpenter's Vampires. Unfortunately, they gave out far too many passes, and the fire marshal made them stop the opening credits to kick a bunch of us out. Luckily, the theater staff told us we could go watch any other movie in the 30 screen suburban multiplex.

I wandered around for 10 minutes until I stopped in my 17 year old tracks at theater number 29, in the far back corner, when I saw the title "Orgazmo". I had never heard of it, never seen any promo for it, but I suddenly had to see it.

I was one of two people in the entire theater, watching a surprisingly heartfelt NC-17 movie made by Trey Parker and Matt Stone about a Morman missionary doing his best in the dingy underbelly of LA's movie industry, and it was a not insignificant part of my decision to go to film school.

I saw This is Spinal Tap in the theater and wrote a rave review in my college magazine.

I definitely saw the first UK runs for Clerks, Mallrats, and Chasing Amy, one of which included a Q&A w/Kevin Smith and Scott Mosier.

Maybe a little less cool is the initial UK run of Dogtown and Z-boys.

Since I moved to the US, Shaun of Dead and Control are the only potential candidates.

A few fun ones:
- Transformers: The Movie (with Orson Wells as Unicron)
- Clue (with each showing having one of four endings)

Also, Book of Shadows: Blair Witch 2 🤦‍♂️

Sidebar: every sequel with "2" in the title has to be suffixed with "Electric Boogaloo". It is the law.

Mad Max 2: Electric Boogaloo
Toy Story 2: Electric Boogaloo
Paddington 2: Electric Boogaloo
Spider-Man 2: Electric Boogaloo
The Godfather: Part 2: Electric Boogaloo

Echoing some of the other responses, saw Repo Man and Dawn of the Dead in the theatre...but I think my most unusual theater viewing was Eraserhead. I don't think it was first run, as it was @1979 and it was released in '77. I also don't think a lot of people had seen it by that time! Another good one I saw early on (hell, there wasn't any "later" for this really) was Citizens Band, an early Jonathan Demme piece with Paul Le Mat, Candy Clark and a bunch of his repertory supporting actors. Finally, I too saw Saturday Night Fever with my mother in 1977 - but I wasn't four, I was 21. My mom was pretty cool.

A friend talked me into going to the first Matrix movie on its first day of release; 10pm showing in Times Square in 1999.

Neither of us, nor most of the audience, had any idea of the plot. At the time it was a thing at late-night Times Square movies that the audience talked back to the screen.

Obviously not an indie -or- individual experience, but unforgettable to have most of the audience reacting out loud, and in real-time, to their first experience of 'bullet time' and the movie's blue-pill red-pill revelations (as much of a poison pill as the metaphor has become in our culture...)

Trainspotting was unexpected and a lot of fun. We made heroin jokes for weeks afterwards.

Idiocracy. I think it ran for less than a week locally, and in only a few theaters.

Run Lola Run, definitely. Also Trainspotting, could have been the same place. All About My Mother and Talk to Her come to mind. Ah, Kendall Square Theatre in Cambridge in the late '90s...

A few years back, I took my kid to see Run Lola Run in a theatre for the 25th anniversary. As a teenager, he was the youngest in the theatre, by far.

I do want to put in a plug for the quirky art places where over the years I've had to go to see great movies. Seeing movies there probably doesn't qualify them for this thread, but...I want to shout them out all the same, because otherwise there's so much I wouldn't have seen. The back room of Bear's in Bloomington, IN; Grand Cinema in Tacoma, WA; the Rio (and now the Park) here in Vancouver.

Iron Giant: I'm a bit of an animation nerd and I went to see it with a bunch of other animation nerds. Absolute delight.
Reservoir Dogs: I was living in Rochester, NY and the Little Theater was screening of Reservoir Dogs. The fellow who wrote reviews for the Democrat & Chronicle spoke enthusiastically about that movie on a radio program and was giving a lecture about the movie at the Little Theater in Rochester after the movie that Friday night. He had so much to say about the film that friend of mine and I went together and we were blown away.
Trainspotting: I was traveling in Ireland in spring of '96. A friend and I had 3 hours to kill before our train to Dublin would arrive. The only film at the theater next door to the train station that lined up with our schedule was this film "Trainspotting", which would not debut in the U.S. until the summer. I knew absolutely nothing about the film going in, and was absolutely knocked over by that film.

Not a small movie, but the most exciting for a 7-year-old kid who loved Star Wars (at the time, it was not known as "A New Hope"). We lived in the northwoods of Wisconsin, with no theaters, stoplights, or McDonald's within an hour's drive.

We happened to be in Chicago visiting relatives and found out we'd be there when The Empire Strikes Back came out on May 21st, 1980. Huge lines, and I got a front row seat on opening day. It was amazing.

Xanadu was a cool movie to me as a kid when I saw it in 1980, and was yanked out of the cinemas pretty quickly.

I have a story in this regard. I do not know how "true" it is. It is an old memory.

There are some indestructible facts. Specifically, I know i owned the 45rpm promo copy of "A Storybook Love". (It was (i believe) the same song on both sides the record. Something that I found odd.) Also, I know this 45 record was NOT something I would have bought.

Here's my memory: I take a date to the local movie theater. (I do not remember what the movie was we went to see.) We show up at the movie theater at the appropriate time and the box office says "You cannot see the movie you want to see. RATHER, you can go see this free movie---called "A Princess Bride"--at the same time as your movie and we will give you a voucher to see the movie you want to see at a later time(day?). Also, here's a free record.

We say to each other: "WTF?!? [yes, this is an anachronism] We have never heard of this movie "A Princess Bride"?! We will come back later"

And that's what we did. (But I kept the record.)

Here's the question: Did this actually happen 35-37 years ago?!?

Obviously not in line with what Jason is looking for but Star Wars was released May 25, 1977. I saw it with my parents somewhere in the first two weeks June 1977. None of my friends had heard of it when I raved at them about it.

It seems that part of "being cool" is being old enough to have been a moviegoer for what became a cult movie, and I have always been an avid theater visitor, and was obsessive in the '90s and had an "art theater" nearby, so I share titles with many on this list, but here I'll start with a few I haven't seen on here yet:
Office Space (opening weekend in big anticipation and loved it)
Spike and Mike's Sick and Twisted Animation Festival
Amelie (twice in U.S. theaters, 1st time on Valentine's Day, not on a date)
Donnie Darko
Being John Malkovich
Naked
The Hudsucker Proxy
Scott Pilgrim
Titus
Requiem For A Dream
Iron Giant (w/a friend who was a huge animation fan)
Shawshank Redemption
Event Horizon
Mulholland Drive
Inland Empire
Bottle Rocket
Rushmore
Showgirls
Welcome to the Dollhouse
Happiness

And some that others listed:
Kids
Gummo
Cabin Boy
Fight Club (twice on opening night because the sound was broken at the first showing)
Usual Suspects (opening night)
Trainspotting
The Big Lebowski
Clue
Mallrats
Crash

First movie I ever saw in a theater was Bananas -- luckily the Orgasmatron went right over my 3-year-old head! Later on my teenage mind was blown by all the great '80s flicks: Eating Raoul, Diva, Repo Man, Blue Velvet, Stop Making Sense...

I saw Men in Black with my older brother in Veracruz, Mexico in the late 90s, the only two non-Mexicans in the theatre. People laughed and screamed, it was very unlike to subdued German movie audiences we were used to, and an unforgettable experience

I was lucky enough to watch MST3K the Movie with friends in a little theater in Albuquerque. I didn't realize until much later that the movie did not have a wide release!

I used to live near the $2 movie theater inside Worldwide Plaza in midotwn Mahattan and would just go see whatever whenever. One night there was just nothing worth even with two measly dollars so I walked over to Times Square and happened on Bottle Rocket. No one had heard of Wes Anderson at that point. That was a terrific experience.

Not sure if it fits the criteria, but my friends and I saw "Kelly's Heroes" during its theater run

We made a trek out of town to see Attack the Block. I don't recall whether or not that was a quiet hit, but it feels like it fits the description.

I saw a press preview of the Matrix. My friends and I went in completely blind, except we knew Keanu Reeves was in it. Truly mindblowing!

Drugstore Cowboy and Sex, Lies and Videotape. Both came out in 1989, kind of the unofficial (official?) start of the indie movie thing. The first movies I'd seen that weren't mainstream, and it changed (positively!) how I felt about movies forever.