Easter Eggs
An Easter Egg is a hidden feature on a DVD
Season 1 DVD and Blu-Ray
In the menu on disc six of the DVD box set, two easter eggs where hidden, one in which Eric Kripke talks to the fans about Season 2 and fan support, and another showing two openers for Supernatural instead of the brief title card that is used. To get to the easter eggs, one must navigate over the images at the side of the menu - the entrance to the easter eggs is activated when a) the door of the house lights up and b) Dean's eyes start to glow.
Season 4 DVD and Blu-Ray
Go to "The Mythologies of Supernatural: From Heaven to Hell" featurette in the Special Features section. In Heaven (Paradiso): Scroll up and highlight "Angels and Archangels". Hit the right arrow. The clouds will be highlighted. Hit enter and Part I of Ghostfacers web video from "It's a Terrible Life" will play.
In Purgatory (Purgatorio): Highlight "The Bonds of Limbo" then hit the left arrow. The doorway will be highlighted. Hit enter and see the Ghostfacers testing their safety goggles. Highlight "Menu" then hit the left arrow, another doorway will be highlighted. Hit enter and learn GMA (Ghost Martial Arts) from the Ghostfacers.
In Hell (Inferno): Highlight "The Sweet Song of Death" and hit the right button. A bar (or something that I can't distinguish) will be highlighted. Hit enter and Part II of the Ghostfacers web video from "It's a Terrible Life" will play.