I used to spend quite a bit of time on the #emacs Freenode IRC channel, but then discovered Discworld MUD, which is like #emacs on steroids: more NPCs (though less advanced ones), more puns (not a fan of those personally, but they create an amusing atmosphere), more locations. It can be quite a time sink, but indeed a fun one. I'm finding it rather strange that those are not more popular, and would recommend to try them too.