http://www.nexusmods.com/newvegas/mods/45511/?
This could be interesting. Still in Alpha, but the option to wander around with a friend or two sounds like it could be fun. No idea how it'll work in practice, though. Quests in particular could be an issue. It's promising it isn't going to be an MMO mod, so that's something. Nothing kills immersion in a game like 50 other idiots doing the same quest at the same time. I think there's one for Fallout 3 as well, but I can't see the appeal. Well, I guess having a friend with me would give me someone to complain to.
Edit: Just remembered most of you aren't PC gamers so I'm not sure what the point of this post is.