Planes, Trains and Automobiles ... John Candy and Steve Martin driving the wrong way down the interstate and they end up in between those to tractor-trailer trucks, that moment where Martin looks over to Candy and see's him as the devil ... classic
The bar room scene in Airplane. When the girl scouts start fighting , hilarious.
Scientific tests have confirmed that the funniest scene ever made is the scene in Borat in the hotel, where borat and his sidekick chase each other through hotel corridors, an elevator, and a conference room. If you haven't seen this scene, then your life is shallow and empty.
Will Sasso from "Mad T.V.", when impersonated Stone Cold Steve Austin. Those were the days.
So many to chose from but a few for me would be Just Go With It when they have the dance contest and Dave Matthews has to pick up the coconut with out his hands.The Nutty Professor when they are sitting at the dinner table.Saving Silverman-many scenes,Rat Race many scenes etc.