Funniest movies ever...
 

1. The Three Amigos

2. Old School

Austin Powers: Goldmember has the funniest credits ever.

The 40 Year Old Virgin is one of the funniest as well.

Old School was also classic.

Office Space is another one that should be on the list.

Best of Show
Waiting for Guffman
Any Chris Rock concert film
The South Park Movie
Friday
Harold and Kumar go to Whitecastle

... off the top of my head.

Friday is hilarious
as are the following:

Happy Gilmore
Billy Madison
Old School

I am a closet Adam Sandler Fan, so I agree, but don't tell anyone.

And I enjoyed Old School, but I don't think I liked it in the way that most people here seemed to like it.

Diner
Harold and Maude
Annie Hall
Dr. Strangelove
Blazing Saddles

No list is complete without...

Raising Arizona
Fletch

Speaking of Coens, how could anyone forget their magnum opus:

The Big Lebowski?

Vacation
Christmas Vacation

Strange Brew