On disc 3 of the box, the one that contains the supplements, choose "Toy Story 2". There, under the "Story" section, highlight "Jesse's Song". On the next screen that appears, press the "left" arrow key on your remote control, and a question mark will appear. With the question mark highlighted, hit "enter" for a funny outtake with an introduction by directors John Lasseter and Ash Brannon.
Also on disc 3, select "Toy Story 2" then go to "History" and then to "The Continuing World of Toy Story". After the video, which you can skip with your remote control, you get a new menu called "Links". It features some story reels of Buzz's cartoon, Woody's nightmare, and other stuff
On all 3 discs of the set, there is a DVD credit screen. To get to them, on "Toy Story" press the "left" arrow key from the main menu. On "Toy Story 2" press the "up" arrow key from the main menu, and on the Supplement disc, in Section 1, select "History" go all the way down to highlight "Menu" and press the "left" arrow key
Yet another hidden feature can be found on the box set. Insert the second disc of the set and then directly access title 4 on the DVD. Please refer to your player's instruction manual how to access titles and chapters directly, as every player is handling this differently. Once selected, you will see trailers for "The Emperor's New Groove", "Fantasia 2000" and "Dinosaur".
All easter eggs were generously submitted by Bjorn_K