Idiocracy may not be the most awesome stupid movie, but its picture is in the dictionary under “stupid movie.” 
I’m torn between Charlie’s Angels and Machete.
Yeah, that one’s "high concept. " I told a friend “I can make you want to see it with two words: moon Nazis.”
Flash Gordon and Machete
I have to second this. We never get tired of watching this film. Son of a bitch must pay.
Before I saw your post I’d intended to nominate a movie that’s played straight, but with a plot that’s ridiculous throughout, and always has a profound emotional effect on me. Evokes many lumps in my throat. Interestingly, it’s another Carpenter film: Starman.
I vote for Step Brothers. My fave Will Ferrell movie with bonus idiocy from the great John C. Reilly.
Lots of great dumbass movies above. To the pile, I’ll add the one that the OP made me think of immediately: The Stupids
To look like a bush you need to think like a bush. Here I am, just being a bush. Just growing and hanging out. This is the life for me. Sure is a lot of soil around here. A lot of sunshine too. As a bush, I notice these things. What’s this? I have arms. I am a bush with arms. And legs. I am the first bush in history with legs! I can walk! Gaze ye non-believers upon this miracle, upon this walking bush. Half man! Half plant! He dwells in two worlds and is a master of both. Oh man-bush. You are nature’s greatest wonder! - Stanley Stupid
Hot Tub Time Machine
Battlefield Earth Stupid stupid science, but awesome freedom fighters with space blasters story.
I maintain that the greatest cult movie of all time, the cultiest cult movie, the ultimate cult movie, is Freaks. What I mean by that description might be the equivalent of what the OP calls the most awesome stupid movie. I’m talking about a film that on a number of levels is clearly bad. It’s badly shot. Some of the plot twists make no sense. The acting is mediocre at best. The dialogue is weak. Despite that, it’s a great film. People might complain just because of the title, which they might offensive. What they don’t realize is that the people in the circus freak show are the heroes of the film. It’s the other circus people who aren’t physically deformed who are terrible humans, who morally act like freaks. This movie will scare you and inspire you despite its weaknesses.
I hope you all see Freaks sometime. Then you too might become a fan of it. Then I can say to you, “Now you’re one of us, one of us.”
Tiny hijack: is the director’s cut worth seeing?
Is the Thing too good to qualify? I’ll watch that every couple of years and always shows many levels of stupid.
I don’t think Pacific Rim was stupid at all; I think it was extremely cleverly constructed to perfectly capture that cartoon universe feel: there aren’t many movies that succeed as well as it did in achieving their aim. And Big Trouble In Little China was a very, very smart movie.
I read somewhere (probably in Cafe Society) that Jack Burton is purportedly the hero of the movie, but if you look sideways at it and consider Jack as the sidekick and Wang the hero, it becomes a (slightly) different movie. When I rewatched it with this in mind, I could see the sense in it.
The movie being, of course, Big Trouble In Little China.
Agree 100%. If you tried to explain the movie to anyone to try and convince them to watch it, they’d not be impressed.
It should have been a flop. But, somehow, they got the chemistry just right. How these things happen - no one knows. They just do.
I’ll also second ID4 - if that comes on the telly, my sunday afternoon is gone. And I know it’s rubbish, but who cares?
These two are my personal choices as well, though Bill and Ted is also worthy.
Seconded, though it’s so far beyond stupid that it goes to awesome and comes right back out on the stupid side. But man - the wig disguise is funny as hell.
I’d also second They Live, The Warriors and Flash Gordon.
I love this movie. It’s a Saturday morning cartoon, only with REALLY high production values. And I saw it with a friend who was a professional trucker, and she loved it. Her comment: “Not enough truckers died.”
It has a lot of non-professional actors in it, which explains a lot of the dialogue. The rest of it is “bad” mainly because the studio took an axe to it, and chopped it by nearly 25%. No one has ever managed to restore a “director’s cut,” if that’s even possible. But at any rate, a cult movie isn’t necessarily a stupid movie. Freaks has low production values for a studio film, and you add to that the non-professional performers, and the fact that the filming schedule was rushed, and you get a project that wasn’t fully realized. It’s not really stupid. A much stupider movie on a similar topic is Sisters, with Margot Kidder, in which Margot Kidder is totally awesome, and I would nominate it, except I think From Dusk to Dawn is a better choice.
As far as the plot twists in Freaks– they’re well explained by the machete editing, but I have a friend who has a theory that none of what happens is actually true. It’s all the barker’s totally fictional story, illustrated, to explain the freak that is Olga Baclanova in a duck costume. Given that most real sideshow freaks did have a phony and exotic backstory, it’s a pretty good theory. Some backstories were as simple as The Elephant Man’s mother was frightened by a stampeding circus elephant when she was pregnant, to the long stories of the capture of the Borneo wildmen, who were actually microcephalics from Brooklyn, in hairy costumes, goaded into acting out-of-control (and possibly drugged as well) in cages.
Saving Silverman!
I love me some classic JCVD. Let’s go with The Quest, Hard Target, Death Warrant, Double Impactand for the truly hardcore gluttons for punishment, try Double Team. With Dennis Rodman. And Mickey Rourke. And part of the movie is literally a remake of The prisoner. I’m not kidding. It exists.