I have a feeling that our vent isn't the only one where if, during a quiet moment, somebody says "do do dee do-do," you are pretty much guaranteed to get a "ma-na ma-na" response. This almost always produces a laugh -- as long as it isn't done too often. The trick is knowing how often.
Bonus youtube link: Manamana (or search for "mana mana" on youtube and take the top link).Vent is the auxiliary program that provides voice-over-ip communication for the whole raid group (geeks in headsets, ftw). It's fairly critical for team coordination during complicated encounters. It also provides a lot of the social fabric that holds the raid group together. The ability to joke around and chat puts the people behind the toons front and center. This seems to be critical for maintaining a team. You have to like hanging around with the people in your raid group. You have to be looking forward to getting into raid chat and getting onto vent in a group like ours. If you don't really want to be there, you probably won't be there.
There are a couple of balancing tricks that you have to pay attention to, though. First is how much talking. You want to tell jokes and chat about irrelevant stuff sometimes, but it's easy for 1-2 people to get a little carried away and accidentally hold up the whole raid. Some people have excellent social skills and very naturally have a feel for how much chatting works. Other people, well, not so much. What? People playing games obsessively who aren't sensitive to social signals? No wai! What you need to do is to figure out how to gently bring those people back on task without being too critical.
Not being too critical is, well, critical, IMHO. I believe this is the most important difference between our raid environment and groups that are more hardcore progression focused. We do not call people out on the carpet publicly for screw ups or poor play. Stay positive, be encouraging, find a positive piece to build on. If somebody really noobed it up, use private whispers to check on them or offer to help, e.g., "is there anything we can do with the positioning?" And never, ever rag on the healers. Healing sucks sometimes. It can be boring and you get very little credit for playing a fundamentally key role. Almost every healer I've ever met eventually gets ticked off about being blamed for wipes and respecs dps. Then you don't have any healers and you can't raid at all.
We also run with relatively little profanity on vent. It's not prohibited and we certainly have some. Being rare makes it even more effective at communicating a strong emotion. The jokes will also run occasionally slightly off-color, but we don't let it really descend into locker room talk. Personally, I don't mind off-color humor, but I've been on a lot of raids and people's sensitivities vary a lot. The more sensitive people really don't feel comfortable speaking up -- often it gets them targeted for even more off-color comments. They just try to hang in, get progressively more uncomfortable and stop showing up. Knowing that this canhappen, we just try to keep things moving. If we get one off-color joke followed by another, you'll hear "and on that note, incoming!" because I'm pulling the next group ready or not. I've seen groups that try to prohibit profanity or change the level of content based on time of day and that just seems to make people even more annoyed.
Once we get into a smaller group (5 or 10) with those of us who've been raiding together for months or years, all bets are off and any topic or level of profanity might break out at any time. If anybody is offended, they aren't going to be shy about saying it and it'll get sorted right quick. But with a random 25 out of 100 raiders, well, when in doubt being polite is a good strategy.
And then there's singing. Hawksy can really sing, and so can Nelmina (but she's on hiatus now, sadly). Other people sing in support, or in contrast or to draw ridicule. It might slow things down now and then, but it keeps the atmosphere right.
Sometimes people move on from l8raid because they want a group with better progression. But I don't think anybody has ever left because they didn't like the environment during raids. In fact, we've had fairly hardcore raiders from progression guilds drop in on our late raids just to hang and help out. I've always suspected they do because we're more fun then their 8pm progression team.
Raiding can be seen as a road to progression kills and phat epix. For our style, though, you have to enjoy the journey as much at least as much as the destination. And that means a certain amount of singing on vent.