This is a tougher question than I expected but if I’m just picking three that never fail to make me laugh no matter how often I see them, I’ll go with several that have been cited ad nauseum above:
Airplane!
Life of Brian
Duck Soup
Having said that, here are the most honourable of mentions:
The rest of the original ZAZ canon, if you can call it that (Kentucky Fried Movie, Top Secret! The Naked Gun), Anchorman, Animal House, Mallrats, South Park: Bigger, Longer & Uncut (the last hour of that film, I was literally crying I was laughing so incessantly when I saw it in the theatre), Scrooged (that’s more a seasonal one, I’ll admit), In The Loop.
Interesting - in most lists I’ve seen, “Life of Brian” always seems ot be the Python favourite, yet, in this thread, it hasn’t appeared yet. Meanwhile “…Grail” has appeared a couple times here - an outcome I totally agree with.
Nuts in May (maybe technically not a comedy - actually no clue what it is)
I see it listed in the “top 3” by four posters (though, admittedly, one of them was the post immediately before yours, and may have been posted while you were writing).
Borat is the movie I laughed the hardest at. That nude fight scene! The single time a movie has made me laugh so hard I genuinely had trouble breathing.
I laughed until I was almost sick at these three. And saw all of them on original release in the cinema. Chemically enhanced, I am sure. I took friends to see each again days later. None of them ran long in those days.
Animal House. Blazing Saddles. This Is Spinal Tap.
A couple of years after Spinal Tap’s soon forgotten run in cinemas it was out on VHS but, in those pre-WWW days, no-one had heard of it. I was in a Blockbuster looking for something to rent and there it was on the weekly rack as a music video. A group of teenage dope smokers was going though the videos looking for stuff and I asked if they had seen it. “Never heard of them.” I don’t imagine that they were looking for viewing tips from someone my age but I explained that it was a piss take - a fake documentary. I told them that, right off the bat, they would hear about all the drummers - all named Stumpy Joe - and one choked on vomit…but not his own vomit. They were convinced.
The next Saturday night I was there again. So were they and they rushed over to tell me how successful their watching was. They hadn’t given anyone else at their gathering a hint what the movie was about. Slowly people caught on and when everyone knew that it as a joke they rewound it and started afresh. That would have been fun.
Happy Gilmore - arguably Adam Sandler’s best movie Half Baked - a “right time, right place” kind of movie for me My Blue Heaven - Nora Ephron-written comedy counterpart to Goodfellas (which came out a month later the same year; Ephron was married to Nick Pileggi when he was writing the book Goodfellas was based on)
Why those three in particular stuck out to me, I’m not sure, but that’s my list and I’m sticking with it.
Borat is genuinely funny. I will never forget him singing the national anthem in front of that crowd. I shouldn’t laugh, maybe? I’m not sure, but I did. I really did.
I’m sure the reactions from the crowd are edited in, but man. I laugh.
I’m so glad I’m not the only one in the world who likes Rat Race. It was the first movie I saw after 9/11 at it was the perfect distraction. To this day, my wife and I still greet misfortune on the highway with “We shoulda bought a squirrel.”
I was curious and came up with the movies most mentioned in this thread. Movies with four or more are:
Airplane! - 14
Monty Python and the Holy Grail - 7
This is Spinal Tap - 6
Young Frankenstein - 5
Animal House - 4
Blazing Saddles - 4
Duck Soup - 4
I took only the top 3 mentioned in a post. And it’s possible I made mistakes.
I made a spreadsheet of the movies nominated and number of votes.
Listed are all movies that received more than one vote.
Column B is total number of votes.
Column C is number of first place votes.
Column E is number of second place votes.
Column G is number of third place votes.
Column I is total points using a weighted scoring system (first place vote = 3 points, second place vote = 2 points, third place vote = 1 point)