DiehardSouljah has posted links to three videos in the High Impact Halo forum; they look like sneak peeks at some of Bungie's as-yet-unreleased Halo 2 maps due out later this summer. They're shakeycam footage, most probably from the E3 floor. Thanks supernostro for the heads-up in #hih.

UPDATE: KP has also posted several small vids of the new Halo 2 maps sent to him from E3. You can view them individually, or download the whole archive.