Easter egg: On the Bonus Features menu, highlight Music and More and hit right. This will reveal a hidden guitar. If you press enter, you will see Demi Lovato singing a song that wasn't in the movie.
Easter egg: On the regular DVD (not the special 2 disc edition), go down to Special Features, press the left arrow then press the up arrow and it will highlight the B and L logo in the upper left hand corner of the screen. It will take you to "Geek-o-rama", a feature about the Pixar employees.