This is difficult because the best comedies are not necessarily the funniest movies, so some super slick screwball comedies like His Girl Friday or the very smart and themes-rich french political comedy The Names of Love do not necessarily score very high on the laugh-o-meter. So, using laughter as the main criteria and trying to spread styles and era:
Blazing Saddles for sure...
Life of Brian
Kung Fu Hustle
The Hangover (or maybe 21 Jump Street?)
Airplane (or maybe Hot Shots?)
Special mention:
- The Marx Brothers, as in a film archive screening of, I believe, The Big Store I genuinely thought one of the aging spectator, unable to catch his breath, was about to literally die of laughter.