Feel free to relate both scripted (eg, planned out) moments that you've experienced in games along with spontaneous (eg, something retarded you happened to witness on an online multiplayer game) ones.
For me, Metal Gear Solid does a great job with the awesome conversations you'll often have on Codec/Radio. Finished playing through MGS3 a little while ago, here are some of my favorites:
Sigint: [while wearing NAKED camo] Snake, what's up? Why are you naked? I know there's a "NAKED" option under "UNIFORM" that lets you take off the upper part of your uniform. But without a shirt on, your camouflage sucks, and your stamina goes down faster. You don't get any advantages whatsoever.
Naked Snake: Sure there are.
Sigint: Like what?
Naked Snake: It feels good.
Sigint: ...Man, you do whatever you want.
Naked Snake: I will, thanks. Just one question, though.
Sigint: What?
Naked Snake: Is there a way to take off my pants?
Sigint: Say what?
Naked Snake: My pants, can I...
Sigint: Aw, hell no! This FOX unit is a nut fest!
Para-Medic: [random conversation after saving your game] Snake, have you seen "007: From Russia with Love"?
Naked Snake: I don't like those movies. Real spies are nothing like James Bond. It's pure fantasy.
Para-Medic: Snake, I don't think the Major's going to like you saying that.
Naked Snake: And even though it's fiction, I can't help but comparing myself to Bond.
Major Zero: What exactly don't you like about James Bond? Is it the fantastic gadgets? The cars? The guns?
Naked Snake: Major...!
Major Zero: Snake, wouldn't you like to have a gun shaped like a pen?
Naked Snake: What good is a pen going to do me in the jungle? I'd look like a fool.
Major Zero: Then what about a snake-shaped gun? You could make it look like you're grappling with a giant snake and then get a shot in on the enemy while they're distracted.
Naked Snake: OK, now you're being ridiculous.
Sigint: [regarding the cardboard box] Uh, Snake... what are you doing?
Naked Snake: I'm in a box.
Sigint: A cardboard box? Why are you...?
Naked Snake: I dunno. I was just looking at it, and suddenly I got this irresistible urge to get inside. No not just an urge - more than that. It was my destiny to be here; in the box.
Sigint: Destiny...?
Naked Snake: Yeah. And then when I put it on, I suddenly got this feeling of inner peace. I can't put it into words. I feel... safe. Like this is where I was meant to be. Like I'd found the key to true happiness.
Sigint: ...
Naked Snake: Does any of that make sense?
Sigint: Not even a little.
Naked Snake: You should come inside the box... Then you'll know what I mean.
Sigint: Man. I don't wanna know what you mean! Between you and Para-Medic, is everyone but me that is hooked up with the Major strange?
Naked Snake: ...
Sigint: Yeah, well, anyway. I suppose even that ♥♥♥♥♥♥♥ box might make a decent disguise if you wear it inside a building.
Sigint: [regarding the Patriot] From the looks of it, it's fitted with a 100-round drum magazine... and it never runs out of ammo?
Naked Snake: Never.
Sigint: Why's that?
Naked Snake: Because the internal feed mechanism is shaped like an infinity symbol.
Sigint: Ah, I get it. Yep, that'll give you unlimited ammo.
I have tons more, but I wanted to keep this first post a little limited so that I wouldn't steal anybody's examples
