What comic elements does the play Hamlet contain? What scenes, what characters what exchanges of dialogue?

The most obvious comic scene in Hamlet occurs in Act 5, sc. 1 with the gravediggers (often identified as the "clowns").  The exchange between the two men digging Ophelia's grave is very funny.  The two exchange riddles and the first gravedigger continues to exchange riddles, as well as word-play, when Hamlet and Horatio come upon them.  Then Hamlet asks whose grave it is that the gravedigger is digging.  The gravedigger responds that since he's digging the grave, it's his.  Hamlet asks is it for a man or a woman, the gravedigger says it's for neither since the one who will lie in it is dead.  And on it goes.  There is some humor in Act 2, sc. 2 when Hamlet and Polonius exchange words because Hamlet is making fun of Polonius only he doesn't seem to realize it.  Also, the exchange between Hamlet and Osric in Act 5, sc. 2, when Osric delivers to Hamlet the challenge to the fencing match from Laertes is humorous because Osric is so fawning and pretentious that Hamlet makes fun of him.