My favorite bit from the commentary track of the Twilight DVD:
Rob Pattinson: "It is so crazy how you were literally two years old in 1998."
Kristen Stewart [somewhat icily]: "I was eight in 1998."
Pattinson does have the best contributions to the commentary. They almost exclusively deal with how he's looking in any given scene. He systematically disses his own plucked eyebrows, bouffant hairdo, confused expression, unscary appearance and poor acting. Kristen Stewart and director Catherine Hardwicke talk about technical aspects of filming and the other actors, but Pattinson is firmly focused on self-hatred.
There is also a moment when Pattinson and Stewart start giggling uncontrollably while Hardwicke is explaining something technical. I don't think it's even during one of their scenes. Finally, Hardwicke breaks off her explanation. "You guys!" she snaps. "WHAT?"
"Nothing," they lie, displaying more chemistry together in that one moment than they do in the entire film.
Got the giggles.