Scads of them, but the Banana Peel example ends the film on a truly classic note.
"Except you, lady. May you just drop DEAD!"
"Okay, so we all agree on that..."
Pike trashing the gas station. ALL OF IT.
"That's it, Irwin— we're gonna have to kill him!"
And the nearby police watching the whole thing in disbelief.
"Holy jumping! They're going back for more!"
"My arm! You broke my arm!"
Then after the whole thing is over, the police move in:
Cop: Are you fellas' alright?
Ray:Now they show up! Where were you when we needed you?
Irwin: Writing parking tickets, I suppose.
Cop:(in disbelief) They're still alive!
The Crumps' attempts to break out of the locked store room.
Russell and Hawthorne's fight. None of their punches connect — they either duck, or just fail on their own (the final shot of them before the intermission has them aim punches at each other only for their fists to collide halfway across). Fantastic.
Then this line after the Intermission:
Hawthorne: Whatever the outcome of the day, I shall never forget that you hit me when I wasn't even looking!
The climactic montage of catastrophe right before the intermission. All the set-ups come to a fantastic finish here:
The Crumps cower in the hardware store basement as fireworks explode all around them.
Meyer's car sinks into the "shallow" river.
The musical sting as the boy waves goodbye to Meyer is the icing on the cake.
Russell and Hawthorne fail utterly in their attempts to beat the tar out of each other after Hawthorne's car overturns.
Mrs. Marcus wails to Emmeline and Pike that she is bleeding after her ride on the runaway tow truck.
Sylvester blubbers frantically as he speeds on his way to "save" his mother from unknown danger.
Benjy and Dingy scream in terror as their plane spins completely out of control.
A thoroughly miserable Culpepper holds two phone receivers next to each other as his daughter cries hysterically over one phone and his wife tries to talk her down by blaming Culpepper for everything over the other phone. Leading to one of Culpepper's subordinates coming in and innocently asking if there's anything wrong.
... and then a pleasant pause with some nice music while you're picking yourself off the floor.
Dingy: What's this coming?! Benjy: That's good, that's cement.
Benjy: Dingy, don't let this worry you: we're gonna get killed.
And the air-control tower trying to talk them down.
Controller: Why don't we just shoot 'em down and be through with it?
And how about when the air control tower told them to stay calm? Dingy and Benjy become calm like they're told, but Dingy quickly snaps out of it in time to see Benjy with a goofy expression on his face serenely letting go of the controls.
Dingy: [Dope slaps Benjy] Not that calm, you idiot!
Also this exchange, when Dingy is trying to snap Benjy out of his frozen fear state:
Dingy: [Dope slaps Benjy a few times] Damn it! Come to!
Jerry Lewis driving over Culpepper's hat, after it got thrown out the window by accident.
Don Knotts's cameo as an (of course) nervous driver, especially since he's paired with con-man Phil Silvers, who covers by pretending to be a secret agent ("Can you handle a gun?").
A wonderful quiet moment in all the noise - as they all frantically dig for the treasure, Benjy suddenly notices the unfamiliar Culpepper next to him. He stares fixedly, then Culpepper turns, stares back...and slowly breaks into a big friendly smile. Benjy slowly smiles back, then turns away with a big, goofy 'yeah, this is good' grin.
Mrs. Marcus in stunned disbelief at how badly her call to Sylvester has backfired, before snapping out of it. "EXACTLY LIKE YOUR FATHER! A big, stupid, muscle-headed moron!"
Also the moment when the other treasure-seekers foil her Victoria's Secret Compartment moment with the car keys by turning her upside down and shaking her.
Pretty much any time Sylvester opens his mouth due to his different manner of speaking. Particularly his last line:
Sylvester: You could've taken a fair share like the rest of us, but no...you had to... grab up the whole scene, baby.