Gee, beg to differ, early Bill Cosby is extremely funny -- The first four or five albums are brilliant word pictures. I have no idea what happened after that (being TV deprived).
The two funniest movies I have ever seen were the first Monty Python film, and La Cage aux Folles. They are the only two films I have ever seen where the audience became giddily hysterical -- that exquisite moment when the audience just cannot stop laughing, and it gets worse. La Cage Aux Folles was particularly good because with subtitles people could laugh, and not be afraid of missing the jokes. There are few moments like that in Mel Brooks ("Springtime for Hitler"), but they don't sustain themselves for me, anyway. They need to build, and build, and build. What you want to do is walk out of the moviehouse or theatre sick from exhaustion from laughing. In the theatre you can do this, mostly in farce (Tom Stoppard's On the Razzle I have seen do this to an audience. Shakespeare's Midsummer Nights Dream done well, and Much Ado About Nothing done well can do it too in the theatre, not on film yet anyway), but in films it is very rare.
As a onetime actor/director, I have been able to induce it once or twice in an audience, and it is unbelievably exhilirating. It is like nothing else on earth. I once was a minor player in a play that did that, and the actors were all backstage afterwards screaming and weeping with joy.
Yours, Peter T.