On disc one, go to [Commentaries] on [Beers and Weirs]. Play one of the commentaries (you can fast forward it). From [Play Commentary 2] press the [Right] arrow to highlight the picture on the wall. This one will reveal pictures that John referred to in a commentary as the "anime" version of he and Lindsay.
On disc two, go to the [Audio Set-Up] and let the song play. When it finishes you'll hear a soundbyte "Why are guys only interested in sex?" and then a McKinley "M" will appear on Bill's ski cap. [Enter] here and you'll get a two and a half minute clip of outtakes from a scene where Sam is waiting to see the school nurse and has trouble keeping a straight face while the kid next to him is crying.
Bonus Chapter Reading
On disc six, go to [Special features] and scroll through all of the [Thanks] pages. Then when you go back to [Special Features] and use your [Right] arrow from [Thanks], a norseman will appear on the DeadHead guy's arm. Press [Enter] and you'll be treated to a chapter reading from "Kick Me" by the author, Paul Fieg.
Bonus Audio Commentary (FAN EDITION ONLY)
On disc seven, if you press [Up] while on the [Deleted Scenes] menu, a Norseman head will appear in the mirror. Select it and there's audio commentary by Sam and Bill in character.
Bonus Montage (FAN EDITION ONLY)
On disc eight, from the [Main Menu], click on [NBC Promos]. View (or FF thru) [Five More Promos]. Then highlight [Five More Promos] and click [Left] to highlight Cindy's chest. By selecting her chest you'll be rewarded with a montage of Sam's dream girl.