The Soprano's clip: Go to the DVD Credits on the disc and all the way to the end, hit NEXT instead of PREVIOUS and it'll show.

The James Caan clip: Go to the family tree, click on Sonny's picture (or is it Caan?).

To see the Godfather in many different languages, go to Set Up, click right with your DVD remote and a globe will show. Click it.

The Mario Puzo one: Go to Mario's bio, forgot where it's at, and click the DVD remote to reveal a $ symbol.

Hope that helps a little bit. I haven't looked at the disc in a while.