As an example, I've never seen a better comedic slip & fall than Philip Seymour Hoffman in Along Came Polly. Most other actors don't fully commit to a fall, because of obvious reasons, one example being Julianne Moore in Evolution, but PSH absolutely goes for it here.
You could argue also that Jack Nicholson is the king of the closed-mouth, shit-eating grin, as demonstrated in Batman, A Few Good Men, Witches of Eastwick etc.