I'm not sure whether or not this is real or what but anyone who has listened to the Superbad commentary will have heard the fight between Judd Apatow and Jonah Hill about half way through. The fight (more of a verbal exchange) seems to me to be too petty to be fake, though it's kinda weird that they would keep it in the final cut of the commentary. Basically the fight takes place because Apatow's young daughter is present in the recording studio along with Jonah Hill. At the start of the commentary, Apatow lays down the law for Jonah, telling him he can't swear in the presence of his daughter. Unfortunately/hilariously, Jonah breaks this rule, several times which eventually culminates in the two having an argument for around three minutes, which comes to an end with JH telling Judd that his job as a comedian is to swear and be vulgar (or something along those lines). At this point, Apatow leaves the studio for the remainder of the recording.
Can anyone recommend any other good fights/disputes on commentaries? Also as today is the 15th of April, and this is kinda related I would like to wish a Happy Birthday to Seth Rogen.