Jean Arthur giving Charles Coburn instructions for their morning routine as roommates in The More the Merrier (or any scene they did together in any movie)
Divine menacingly eating a meatball sub in homeroom in Female Trouble:
James Franco putting his foot through the windshield in Pineapple Express and then screaming while struggling to take it out was one of the funniest things I had ever seen when I saw it, and will probably always remain so
Jerry Lewis don't answer no phones and don't eat no breakfast