I am entirely certain My Dinner With Andre is some kind of inside adult joke I have never grown old enough to understand.
That’s my pick.
I did try Stand and Deliver with my 10 and 13 year old a year ago. They noped out of the math minute one.
The Black Hole (1979) “You’ve seen Star Wars, right!? This came out a year later and is like that only not any fun.”
I think My Dinner With Andre is the clear thread winner, unless we decide it’s not “mainstream” enough.
As WildaBeast said, though, any film with subtitles is going to have a big advantage here. Skimming IDMb’s 250 most popular films list, and looking only at the small minority of those films I’ve seen, I might go for another German film, The Lives of Others. It’s a film about the East German Stasi which I think is trying to illustrate Hannah Arendt’s point about the “banality of evil” by showing how much of their work was just spying on ordinary boring people and then having boring conversations about them. I think it’s an excellent psychological thriller, but would be completely unappealing to a child. It’s maybe not well known, but did have a theatrical release in the US.
Similarly Logan’s Run is very kinetic. Plenty of running, chasing and shooting. That would probably appeal to many youngsters. Plus for a few the theme of an ever-young society.
Solaris, Phase IV and Soylent Green in about that order from most to least are slower. Phase IV might work for the bug-obsessed, Soylent Green might hold attention long enough for the iconic ending. Maybe. Solaris…yeah, Solaris will lose them.
The thing about The Sound of Music, which I recently rewatched, is that it would be a perfectly good 90-120 minute movie, but it lasts for three hours. Apparently length for the sake of length was considered a sign of great cinema in those days, so there are many scenes where characters just pace around and perhaps gaze out a window for minutes at a time. All the songs go on for a few more choruses than they needed to. It’s really boring.
The Dead.
Beyond that, while the theatrical version was 149 minutes, the director’s cut is 208 minutes and the original uncut miniseries is 308 minutes. All in German with subtitles. You can bludgeon an American kid to death with that 
.
Is it really so obscure in the US? “The Lives Of Others” won the Oscar for best foreign movie after all.
Didn’t it also have some brief partial nudity? That was enough for me to watch it as a kid. I also liked Soylent Green.
Ha! I just watched that (again) on Friday (annual MSHA refresher).
Weirdly, mine did too! The only other movie I ever remember being taken to in school was “Gandhi”, which has obvious educational value.
Do you mean the 2000 Tom Hanks film Cast Away? Because the compound-word version of the title is throwing me a bit, but I don’t know of any other major film by that name, so that’s how I interpreted it.
In any case, if so, then I agree with you about not thinking the movie was particularly good or enjoyable, but I don’t know that I’d have called it “boring”. I mean, plane crash, dead pilot, survival, random flotsam supplies: a lot of stuff that kids would find immediately comprehensible and possibly intriguing.
After all, kids used to read Robinson Crusoe, and that’s quite a slog IMHO.
My uncle insisted that I needed to watch Excalibur before being able to enjoy Monty Python’s Holy Grail; which is odd now realizing that it came out 5 years after the Python film. I was ~14 at the time and found it to be extraordinarily boring.
Oh, and there is a bit of an implied orgy. Teen Sitnam would have been paying attention for that part. Also chasing and some violence so almost a toned down A Clockwork Orange.
Now that is a film that wouldn’t bore a child, but traumatize.
I thought it was going to be a another ‘Band of Brothers’ but in a Pacific theater setting. I was wromg: big time.
I would suggest 12 Angry Men. A bunch of guys just talking
Just gonna mention a lot of these movies would serve as punishment for adults also.
We tried to watch The Master in the cinema a few years ago but my friend and I were bored to tears so we left halfway through. I realise this may be a controversial opinion.
I fell asleep every time I’ve tried to watch The Godfather.
And what about Solaris by Tarkovsky? That long camera shots of highways or Bruegel’s paintings - I doubt kids would appreciate symbolism.