What is the single funniest movie you've ever seen?

Caveat: I’m not a huge fan of comedy films, so I haven’t seen a lot of the classics. I just saw Young Frankenstein about a year ago and I fell asleep. I thought it was boring (and I love Gene Wilder).

That said: Probably The Birdcage. That one still makes me laugh after all this time.

“You’re going to kill yourself…and you’re taking your toothbrush. How Egyptian.”

That’s funny. If I had been asked what your favorite Cary Grant comedy was, I would have guessed Arsenic and Old Lace.

Planes, Trains, & Automobiles
Christmas Vacation
Dumb & Dumber
There’s Something About Mary
Best in Show
Monty Python & the Holy Grail
Pineapple Express
Superbad

Another of my faves, and infinitely better than the overdone remake. The low-budget production values only added to its wonderfulness.

The Devil (Peter Cook): It’s a terrible bunch of sins I have working for me. Must be the wages.
Not to mention the offhand way he goes about wreaking havoc (ripping out the last few pages of Agatha Christie novels, making parking meters expire, cutting holes in the sides of ships) while simultaneously talking theology with Dudley Moore.

I’d vote for The Party. Funniest. Movie. Ever.

I’m always surprised when I hear someone say they didn’t enjoy My Cousin Vinny and am likewise surprised that it’s not been mentioned yet in this thread. I thought it was hilarious and many of the scenes had me roaring. Yeah, sure, it’s a bit uneven, but I don’t think there’s a funnier flick out there.

I’ll also point out that, when it was released (circa 1971) and I was young and very stoned, The Ruling Class was the funniest thing I had ever seen. Alas, it may have have lost a bit of its lunatic lustre these past forty years.

I laughed at a lot of Grizzly Man. Yes, the story had a tragic ending but most of the movie is footage that Timothy Treadwell shot of himself in Alaska, and he is hilariously fey, odd, dramatic and deluded, with a passion for deadly grizzlies similar to that certain old women have for teacup Chihuahuas. Which is why he got himself killed, poor fool.

For my money I laugh the hardest at rapid fire farces so I’ll put yet another vote for Noises off. As a second choice, Room Service by the Marx brothers. For a subtler comedy I’ll go with Tampopo.

The Holy Hand Grenade of Antioch
The Black Knight
French Taunters
The Knights Who Say “Ni”
Brave, Brave Sir Robin

One day son, all this will be yours
What, the curtains?

C’mon, you know what I’m talking about.

For a movie with sound this is also the film I find to be funniest.

But I’m a silent film fan, and if you’ve never seen Buster Keaton in Seven Chances then you have missed something special. This movie was remade as The Bachelor, starring Chris O’Donnell, and it proves that sound, color, and special effects don’t necessarily make a movie better.

My favorite scene in Seven Chances is when Jimmie bribes his way at the stage door, to propose to what he thinks is a dance hall girl. He doesn’t realize it’s really a female impersonator he’s going for. Modern day audiences may not have heard of Julian Eltinge, but he was the best known cross-dresser of his day, and if you were sitting in the audience back then you would have been howling when poor Jimmie staggered out with a window frame smashed over his head.

Team America World Police.

It’s not my favorite comedy and I’ve only seen it twice but I’ve never laughed as much or hard at a movie.

A Fish called Wanda, Borat, Death at a Funeral (UK version) and The Full Monty are all up there for me , but the answer to the OP has to be

Airplane!

Probably a tie between Airplane! and Young Frankenstein.

I remember being in hysterics over one of the Pink Panther sequels in the 70’s, but can’t remember any specifics.

But I think the most I’ve ever laughed, literally falling out of a chair and wondering if I’m about to have a heart attack, has been at an episode of MST3K (probably Space Mutiny) – but that’s not a funny movie, it’s a bad movie made funny.

The hardest I can remember laughing at a movie was There’s Something about Mary.

Office Space is my favorite, although The Big Lebowski is pretty awesome too.

For sheer number of jokes I would 20th Airplane! and 2nd (I think) Superbad.

I have to agree with Chefguy on this. It doesn’t hold up as well as some of the others mentioned (particularly compared to Young Frankenstein) but when it comes down to seeing it in the theater for the first time with a bunch of strangers, BS was the most hilarious 93 minutes I’ve ever had in my life.

Surely you can’t be serious.

“Harold and Kumar Go to White Castle”

I have the sense of humor of a twelve year old boy.

Airplane!, followed by Animal House, and finally the original The In-Laws.