I don't believe anyone has mentioned this yet, but there is an Origins easter egg in the game. In Origins, the truck that Travis is driving says "AMBROSE Trucking & Hauling" on the trailer. Seen here at 1:05: http://www.youtube.com/watch?v=58MDJeXcU-A
"Chaos is merely the realm of the infinite possibilities. Imagination is merely a spinning wheel pulling threads of reality from that realm. Thought is merely a loom weaving those threads into the fabric of existence." -Someone
In the tell tale heart side quest has anyone noticed the uncanny resemblance between the corpse and Adam Shepherd? Its been nagging at me since I first played : The corpse is also dressed in what seems to be military uniform.
yess i did !XD we all said that he looks like John Locke too! XD that was a military uniform.?!O.O i thought it was a prisoner uniform just as the rest of the prisoners as for murphy too... right!?O_O...hmmm...O_O...
She's a hard work lover, a real tough mother, she's the cover of a magazine And I'm happy knowin', that what keeps me goin' is what's gonna keep me comin' back She's my honkin' tonkin', everything I'm wantin' Cowboy Cadillac
Not sure if anyone has said this, but the song Born Free which we hear played several times is an actual song in real life.
The country song that plays on the radio in the parking garage of the Centinnial Building is also an actual song. My dad and I recognized it and have heard it on the radio several times. I'm not sure if the others are as I don't recognize them, but those two are real.
And I'm sure someone else has said this, but the things you dig up in the "Digging Up The Past" quest, are all East Eggs to past games.