Screaming Penguin

I realize this wont matter to most users here, but if you are like me and have kids this is pretty cool (and Monsters Inc is a great movie kids or not).

There are some easter eggs in the Monsters Inc DVD that allow you to see the Pixar staff having a paper airplane contest, more bloopers, animation shorts, etc.

The details are below as taken from DVDReview.com

Monsters, Inc.
On Buena Vista Home Entertainment’s Collector’s Edition release of the Pixar feature 'Monsters, Inc.' you can find some additional hidden material if you know where to look.
Insert the second disc of the set – the one with the Bonus Materials. From the main menu, select the door that says 'Monsters Only' and in the following menu screen press the 'Right' arrow key to highlight the eye in the 'Monsters, Inc.' logo. Press 'Enter' and you will be treated to some animation test footage reels with an introduction by director Peter Docter.
Now, go back to the main menu, and this time select the door that says 'Humans Only.' In the following screen, highlight the 'Pixar' door and then press the 'Down' arrow key. This will take you to a section of DVD credits.
Also in the section for Humans only, watch the 'Production Tour' all the way through and in the end you will see a screen with a number of untitled doors. Each one of these doors takes you to another unannounced feature on the disc, including test footage, bloopers and more.
A third Easter Egg is hidden in the 'Humans Only' area of the disc. In that area, select the 'Pixar' menu entry and in the following screen, highlight the door that takes you back to the main menu and press the 'Left' arrow key on your remote control. This will highlight a flight trail for a Paper Airplane that is flying in circles. Press 'Enter' and you will be able to see some footage of the Pixar staff having a Paper Airplane Competiton.
These hidden features have been first reported to us by our readers Daniel Lock and Justin Manuel.
  DVDReview.com: monsters inc easter eggs