I just rewatched Ruthless People after 10-15 years and couldn't stop laughing. Bette Midler is an underrated actress/comedian and Danny DeVito is always a riot. If you pay enough attention, you will see "Frankie Carbone" of the movie Goodfellas in a scene.
Highly recommend.
Down and Out in Beverly Hills is also great. (Just rewatched as well)
What About Bob?
There are others I'm going through from the 80's early 90s.
Noises Off is about as hard as I laughed at a movie.
It takes a bit to set up the payoff, but when it's in full swing of the hijinks, it just comes at you in waves.
Hardest I laughed at the theatre was probably Something About Mary. [Reply]
Spaceballs, Uncle Buck, Coming to America, Ace Ventura,National Lampoon's Christmas Vacation, Robin Hood men in tights, Don't Tell Mom the Babysitter is Dead, Look Who's Talking, Mrs Doubtfire. [Reply]