There are some great ones on the metafilter discussion of this site. I did not do either of these.
Stranger: wsup
Stranger: hey
You: Hi. Do you think this is really a good idea?
Stranger: stfu i don't wanna hear about your ideas faggot
Stranger: we're not cybering pedo
You: Heh, I figured. Thanks.
Stranger: i'm just trying to kill time in economics
Stranger: what's up with you
You: Wanted to know what the hell this thing was.
You: Now I know.
You: Later.
Stranger: wtf
Stranger: dont leave me
Stranger: hi
You: Are you there?
You: I'm you from the future.
Stranger: How did you know?
You: I would warn you of impending doom, but you lead a really boring life for the next couple of years.
Stranger: I am from the year 2015
You: You never really amount to anything.
Stranger: My name is Marty Mcfly
You: No, no, I'm from the far future.
You: Where hoverboards DO work on water.
Stranger: THEY DO?
Stranger: Take me with you
You: I can't take you back to the future.
Stranger: Not even at 88MPH?
You: Not without Huey Lewis.
Stranger: With or without The News?
You: Normally people disconnect by now.
Stranger: They are weak. They are from the past.
You: Zombie huey lewis is just as good.
You: We ought to send robots back to kill everyone's mother.
Stranger: Yes. I heard there was this guy called John Connor.
You: In the far future, we give the robots John Connor and they leave us alone.
You: It was really obvious, in hindsight.
Stranger: I never saw that.
Stranger: I was just really happy with my hover board
You: Still no jet packs.
You: Or flying cars.
Stranger: Doc is working on it
You: how many gigawatts do you guys have?
Stranger: 1.20
Stranger: just 0.01 left
You: holy shit!
You: 1.21 gigawatts!?
Stranger: Amazing isn't it?
You: 1.21 GIGAWATTS?!?!
Stranger: 1.21 GIGAWATTS!!!
You: UNO DOS UNO HEEEGAWATTOS?!?!
Stranger: SI
You: oh, ok.
Stranger: The flux capacitor is acting up though.
You: It's really just a coat hanger, ya'know.
Stranger: Thats what people have been trying to tell me. I still have faith in Doc.
You: ok, I'm going to get back to the future. we have eloi to rustle.
Stranger: Godspeed to you good sir.
You have disconnected.
http://www.metafilter.com/80436/Omegle-like-a-slot-machine-only-with-people