I was playing Portal 2 today and discovered an Easter Egg:
In Chamber 03 of Chapter 2 Wheatley is staring at you from underneath where the panels have been lifted up!

If anyone found this before me, Say so!

Not only that, but you can actually grab Wheatley in certain chamber also.

He also appears behind a panel next to the victory lift in chamber 07, right after the second WCC gets fizzled.

We know, thats where you can grab him. He appears multiple times through that part of the game.

That's

spongylover123 wrote:
That's

And for him

Far away from cOLD.

OK, to clear some things up:

1. I KNOW Wheatley is found in some test chambers
2. I did not know if this particular one had been discovered yet
3. RYEDHFFFGGGH!!!
4. 
5. What?
6. Ummm...
7. I CAN'T LIVE ANY MORE
8. 
9. 
10. 
11. Uh oh

Random rage over. Everyone head on back to your desks.

ZZZzzz... Whaa?!
CAROLINE! GET ME MY CAMERA! I NEED TO PROVE THIS EASTER E...

I've just bought the game for someone some days ago who never played any Portal before. Then I watched him playing the game (he is not through it yet). He noticed some of the points that you call "eastereggs" on his very first look. Non-hidden eastereggs are no eastereggs!

Well, to be fair, Wheatley appears only once in the room and it's kinda hard to notice him on the first time through.