If you havent seen "Due Date" its a year or 2 old but its really good.

If you have the time give 60's screwball comedy IT'S A MAD, MAD, MAD, MAD WORLD a shot,
[http://www.imdb.com/title/tt0057193/
About as funny as funny gets. Genius ensemble cast. Recommended!

Monty Python and The Holy Grail
Monty Python's The Meaning of Life
Bubble Boy-the offbeat one
Hamlet 2

My all time favorite comedy is The 'Burbs. I have seen it a thousand times and it never gets old. I also like the Fletch movies and Ace Ventura ones as well.

I confess one of my faves is What's Up Doc - somehow they crammed into a relatively short film myriad classic devices: mistaken identities (of people and objects), good old gags (well, whole storms of it... probably a good 20mins toward the end of the film are a direct hommage to the silent movies' great chaotic chases), physical comedy, linguistic comedy (at a speed that is sometimes dazzling), superb acting even in totally episodic roles, cartoon-esque turns of events, archetypal characters, action and surreal comedy overlapping completely...
True, it is not inventive in the strict sense, but I just marvel at how the script managed to create this texture of gazillion great comedy moments of very different nature... and somehow they all work together

I love CHASING AMY. It is a great look at the complexities of human sexuality and love, and it's one of Kevin Smith's best and most well-made movies.

I can watch, "Raising Arizona" over and over again.

I love Monty Python's work. All of it is good to me.