To unlock these goodies, go to the main menu. Watch the stove in the upper left-hand corner of the screen... and wait. Soon, a rat will peek around the stove, and we he does, click the Left arrow on your remote. This will unlock a hidden menu with five different items.
Among the tasty treats is a mock "Ro-Dead" commercial for rat poison, a vignette with producer Brad Lewis playing the trombone for the orchestra, additional fake outtakes, and a special treat the film's CGI actors cooked up for the director, Brad Bird.
All easter eggs were generously submitted by a3willia