Go to the [Special Features] menu, then choose [The Philosophy of Time Travel]. Once you have done so, continue to press [Righ on your DVD remote until you come to the page titled "Appendix A". Press [Up] on your controller to highlight the circle, then press [Enter]. You will see an extra deleted scene.
Bonus Trailer
Return to the book, and go to the page titled "Appendix B". Press [Up], and a black arrow will appear. Press [Enter] to see another trailer for the film.
Website Gallery
Go to the [Special Features] menu, and choose [Cunning Visions], once in that section, highlight [Special Features] at the bottom of the screen. Now press [Right] on your DVD remote and the small Cunning Visons logo will be highlighted, then press [Enter]. You will now be taken to the Donnie Darko Website Gallery section.