I love secret messages (well, they're not really secret messages, just easter eggz, but I still loves 'em).
I'm searching for a few more.
This is off-topic, but I dont want to open a whole new thread just for this:
In Doom, when you enter the room containing the Icon of Sin, the "final boss", an odd message plays. Its supposedly the Icon of Sin speaking in a weird language. In reality, its a voice-masked message from John Romero (creator of Doom and video game visionary), saying "To win the game, you must kill me, John Romero," being played backwards.
Ok, so what does this mean? In this final level, you are supposed to use rockets to destroy the Icon of Sin. Actually, within the Icon of Sin (you can walk right through it), the animated head of John Romero sits impaled upon a spike. The rockets are supposed to do splash damage to the head. Once the head dies, you win. Shooting the Icon of Sin with any other weapon does nothing at all, because the Icon is not the real end boss.
Our friend John made this message as a way to get back at the developers for putting his head in the game.
Again, off-topic, but, meh.