I am surprised that “Animal House” was not on the list. I remember watching it in the theater in 1978 and it seemed like the entire audience was laughing continuously.
And speaking of Monty Python, when I first saw “The Meaning of Life”, I laughed for almost a half hour at the Restaurant skit (Mr. Creosote). It was maybe the longest, deepest sustained laughter of my entire life. Luckily, I saw it on video in my own home and was not in their theater (as I probably would have been ejected).
The “Biggus D!cku$” skit in “Life of Brian” may have been a distant second. To this day, I cannot watch that scene without cracking up.