Funniest of all time is really hard for me. It depends on my mood. I honestly think comedy is one of the hardest things to do in film. I'll list a few of my favorites:
- Airplane! - when this came out, no one had seen anything like it before - still hysterical
- This is Spinal Tap - great, great movie - I think you probably have to have a strong interest in rock music to really "get it," but I think it's terrific
- A Fish Called Wanda - I remember this being laugh out loud funny when it first came out - I don't know if it's held up very well - I saw it recently and wasn't as moved to laughter
- Bull Durham - this movie seems to be very devisive - I thought it was great - there are others, for a variety of reasons, who can't stand it (hate Kevin Costner, hate Robert Wuhl, think it's a chick flick instead of a sports movie, etc.)
- Caddyshack and Animal House - classics - still quote them all the time
- Fletch - another classic in my book - when Chevy Chase is on, he's really on (too bad it's not all that often)
- National Lampoon's Vacation - more Chase - great film
- Foul Play - even more Chase - however, watch it for the brief scene between Dudley Moore and Goldie Hawn
- Parenthood - took a seemingly ordinary subject and made a very good, very funny film out of it
- Monty Python's various offerings - none of their movies have blown me away from beginning to end, but all have several great comedic moments
- Blazing Saddles and Young Frankenstein - Mel Brooks' best, IMHO (hold up much better than the original Producers)
- Shaun of the Dead - a more recent offering - very good
I'm sure I'm missing some, but no doubt there are others here who will pick up the slack.