Easter egg: On the feature disc in the menu where you can access the director's commentary and deleted scenes, click to the right to see a baseball player light up. The director will explain who the voice is.
Easter egg: Go to the end of the special features menu and press down on the "main menu" tab and the zebras ears will change colour. Press enter to see a short with the rooster.
Easter egg: From the main menu, scroll to special features. Hit the up button twice and then hit enter.
Easter egg: On the Special Edition version, go to page three of the special features, go to 'main menu' then hit left, and you can highlight the knife that Jennifer holds. The easter egg reveals a selection of stills from the movie.