The "alternate ending" is a joke (and a rather funny one, IMO), as is the displayed commentary track (less funny, involves Vaughn, Stiller and the director getting drunk, fighting, and ultimately walking out, forcing "interns" also voiced by Stiller and Vaughn to play the commentary track to There's Something About Mary instead). There are 2 real commentaries though (one with cast, one with director), which are available as easter eggs.