On disc one, on the commentary menu, highlight the the "Main Menu" button at the bottom of the page and press your Up button. Click on the highlighted monkey and you will be treated to a couple minutes of a bonus commentary.
From the main menu select "Special Features" and then "Cast & Crew Profiles" and finally "Cast". While most of the entries here contain just text based entries, those for Estella Warren, Erick Avari and Luke Eberl all have additional audition tape sections.
Go to "Languages" selection on the first disc. Go down all the way and push the right arrow key on your remote and you will highlight a picture of an ape head with a helmet on push on it and you'll see the DVD credits.
All easter eggs were generously submitted by SirDonk