Meh... Hard to pick just one, but I’ll second the following:
Airplane
Blazing Saddles
Caddy Shack
Big Trouble in Little China
Young Frankenstein
It’s a madx4 world
Blues brothers
Animal house (though wearing on me lately)
and Add:
Any Charlie Chaplin full length
Princess Bride
Monty Python’s Holy Grail
Sean of the Dead
Army of Darkness
Raising Arizona (just one line is enough: lone biker of the apocalypse)
Harvey
This is Spinal Tap
Planes, Trains, & automobiles
The Thin Man (any of the 4, older, different humor)
Philadelphia Story (1940)
Duck Soup
Arsenic and Old Lace
Paper Moon
Bad News Bears (original only)
Ghostbusters I
Odd Couple (1st)
Aladdin (Yes the Disney cartoon, me and a bunch of other junior officers laughed our ass off first time we saw this)
For a stretch or something different:
Any Abbot & Costello, Laurel & Hardy, Ma & Pa Kettle, Hope& Crosby Road shows, or Marx Brothers (other than duck soup)
Ground Hog Day
Shrek I
Tommy Boy
O Brother Where art Thou (if only for the song)
Big Lebowski
Dumb & dumber
Spaceballs
Beetlejuice
Stripes
MASH
Dodge Ball
Blades of Glory
Trading Places
History of the World Part I
Sorry I got to reminiscing and got carried away -— those are the ones I can think of off the top of my head. The last list wears on me a bit if I see them too much. With the exception of “BT in LC” and the older B&W movies the 1st and 3rd groups tend to be a bit more for a selective crowd due to language and inuendo. There’s a few in the second list like that but not nearly as bad.
Love Arsenic and Old Lace.
Cary Grant was comedic genius.
Raising Arizona was a great underrated film.
Glad you mentioned Big Lebowski. That may actually be my favorite comedy. And also glad you included Shaun of the Dead. That whole trilogy (Shaun of the Dead, Hot Fuzz, and The World’s End) is great.
Oh yes, The Big Lebowski.
John Goodman deserved an oscar.
The scene in the diner when they’re talking about the “finger” is too dang funny.