Linkin Park: Frat Party at the Pancake Festival Easter Egg - Secret Scene with Personal Footage Form the Band

You need to get to Title 3, Chapter 1. On my DVD player, you need to stop the DVD and hit the Goto button and enter it in. I've heard on some other DVD players, you can enter it using the Program button. There's 12 minutes of hilarious backstage footage and a few clips of live performance within. To my knowledge, it's the same footage that's on the UK "Crawling" single in Quicktime format.
There's more Easter Eggs to be found, but according to Mike Shinoda of the group, you need codes to access them, and they'll be giving the codes sometime next year!