Some versions of Netscape, Mozilla or Firefox will display a verse from "The Book Of Mozilla" that comes across a bit like a verse from The Book Of Revelations in the Bible on a maroon background. Here's an example.
And the beast shall come forth surrounded by a roiling cloud of vengeance. The house of the unbelievers shall be razed and they shall be scorched to the earth. Their tags shall blink until the end of days.
from The Book of Mozilla, 12:10
Read the real story behind "The Book Of Mozilla"
Some easter eggs can be found in DVD movies too. Some of George Lucas' films have hidden videos. If you press "1138" on the DVD remote when the "THX" logo has been highlighted, it unlocks extra blooper reels and stuff. Lucas' first film was called THX 1138.
MrMadson from Little Gamers has a Flickr site.