After The Part Where He Kills You, you enter the area where Wheatley says he's "holding all the cards" and you use the Excursion Funnel to get to the spiny blade wall. If you exit the excursion beam while he says "I see, clever, very clever" and land on the hanging rail he'll say something funny. Repeating entering and exiting the Excursion Beam will make Wheatley say more funny stuff.
Spoiler:
1st Enter:"Ah, I see. Clever. Verrrrrrry clever."
1st Exit:"No wait, come back. Sorry. Please. I was going somewhere with that."
2nd Enter:"FOOL! You were a fool to come back, because I've trapped you again...
2nd Exit:"And again, not playing along. You're ruining what are some really good speeches, actually."
3rd Enter:"Puppet master! You're a puppet in a play, and I hold all the strings!"
3rd Exit: "Didn't even get to the good part yet. Twist ending."
4th Enter: "So twisty you might even call it spinning."
4th Exit: "Alright, fine. I'm not saying another word until you do it properly. I'm sick of this."
Some of these quote go longer but an interrupted when you exit the Excursion Beam

It appears I started an easter egg hunt with my topic.

Nice find though.

Lostprophetpunk wrote:
It appears I started an easter egg hunt with my topic.

Nice find though.

Actually, I already posted a few easter eggs earlier before the topic. Too bad there isn't a "Post Portal 2 Easter Eggs Here!" topic.

MasterLagger wrote:
Too bad there isn't a "Post Portal 2 Easter Eggs Here!" topic.

Perhaps the threads ought to be merged.

I beat all of you.

http://forums.thinking.withportals.com/portal-two/portal-2-easter-eggs-spoilers-probable-t2283.html

laughs evilly

Unfortunately, it's been dead for a few months. Want a defib post for you topic the next easter egg I find?

I wouldn't mind either way.