DVD's with commentary
I have been watching my movies with the commentary on and have learned alot about what the person was thinking and what they did because of it.
In this, Donald Petrie gives a lot of what he did and the improvs that he allowed. A lot of people don't like this movie but I like it even more because of the commentary. Ray Ramano did a lot of improvs that he "gave away" to other actors in the scene that made it even funnier. He did some funny lines himself.
I watch all my movies with the commentary on at some point and gain some insight as to what the actors, writers, producers, directors and etc are thinking. It's pretty interesting.
Just a thought.