Airplane
Office Space
M*A*S*H
Rocky Horror Picture Show
The Birdcage
Raising Arizona
Fargo
Monty Python and the Holy Grail
Cat Ballou
Better Off Dead
Good Morning, Vietnam
Police Academy (only the first one)
A Night at the Opera
Abbott and Costello Meet Frankenstein
Casino Royale
Sleeper
The Trouble with Angels
Men in Black
King of Hearts
Young Frankenstein

I know I'm going to think of more as soon as I enter this post ...

The Grail (I'm pretty sure this is the funniest film of all time)
Blazing Saddles
Young Frankenstein
High Anxiety
A Shot in the Dark
Skin Deep
Victor/Victoria
Operation Petticoat
The Bird Cage/La Cage au Folles
Top Secret
Airplane
in fact...pretty much anything by the Zuckers
Kentucky Fried Movie
The Naked Gun - All of 'em
My Favorite Year
A Night at the Opera
Monkey Business
Bringing up Baby
Arsenic and Old Lace
Harvey
Clerks

The Birdcage and La Cage aux Folle have to be treated as separate films.

Because, well, they are.

La Cage is amusing. The Birdcage is as funny as shit.

I just wanted to give acknowledgement that one begat the other...although I guess I sort of put them in the wrong order.

Harold and Maude
Animal House
The Graduate
Wierd Science
Real Genius
The Odd Couple
The Breakfast Club

(I really better stop now ... I could go on and on and on ...)

Do stop at 20!

Election
Young Frankenstein
Sleeper
Blazing Saddles
A Night at the Opera
Ferris Bueller's Day Off
Heathers
Mallrats
Fast Times at Ridgemont High
Ed Wood
Monty Python and the Holy Grail

airplane
caddyshack
porkey's
ghostbusters
waterboy
the birdcage
back to the future 1 (comedy? dunno, but i laughed a lot)
50 first dates
aladdin (disney one, with robin williams as the genie)
forrest gump!!
splash
goonies
first wives' club
maverick (god is mel gibson HOT in this...)
bird on a wire
as good as it gets
witches of eastwick

You guys have pretty much covered everything I can think of, so I'll let my input help with the seeding.

Monty Python and the Holy Grail
Blazing Saddles
Spinal Tap
Fast Times at Ridgemont High
Caddyshack
Blues Brothers
Better Off Dead
Real Genius
Stripes

oh yeah, did anyone mention:
A Fish Called Wanda?

These have been nominated, but gotta get my $.02 in.

MP & Holy Grail

Spinal Tap (the first time I saw it, I literally almost passed out from laughing at the Stonehenge bit)

Office Space

What About Bob?

Any Sellers Pink Panther movie.

About a Boy
Love Actually
South Park Movie
What Lies Beneath

All film titles I repeat should be read as "seeding votes" since I agree with many exisiting nominations.

1 -- The Gods Must Be Crazy
(The "anti-christ" Land Rover at the gate is exquisite physical comedy)
2 -- Me, Myself, and Irene
3 -- Young Frankenstein
(What Knockers!)
4 -- Modern Times
(Chaplin, the father of physical comedy)
5 -- A Fish Called Wanda
(What was that part in the middle?)

/retires to think of 15 more.../

Napoleon Dynamite!

6 -- Some Like it Hot
7 -- There's Something About Mary
8 -- Monty Python and the Holy Grail
9 -- Aladdin
(You ain't never had a friend like me!)
10 -- Mrs. Doubtfire
(more Robin Williams insanity)

11 -- Duck Soup
12 -- Raising Arizona
13 -- Rocky Horror Picture Show
(Rocky! Ughh!)
14 -- Groundhog Day
15 -- A Shot in the Dark
16 -- Mask
17 -- The Seven-Year Itch
18 -- Airplane!
19 -- Monty Python's Meaning of Life
20 -- (twenty already?!) Singin' in the Rain
("make 'em laugh")

only 20? /sigh/ Let the games begin!