I have a BS and would like a PhD. I have the base requirements+ for all programs. I called places that had professors I wanted to study with. One professor has called me several times to discuss a proposed thesis plan and funding.
I've not interviewed yet. I've been invited to come down and meet the "team" - will probably do interview that day as well. The interview doesn't worry me, But meeting the "team"? Am I expected to have brilliant stuff to say? I want this position, and I am worried that I'll say something stupid.

Just be yourself! It's a good opportunity to see if you are likely to enjoy working with these people. Don't try too hard to impress, just be enthusiastic and interested in the proposed project and the work that the other researchers are doing. As for what to drink at the bar (your next question), while it's not a good idea to get plastered, I'm sure you'll be alright to have one alcoholic drink (if you want one!) especially if others are drinking. But if you're worried, have an orange juice. Good luck :o)

Pamela , you said that you had the base requirements+ for all programs and the interview didn't worry you so you should believe you will be good then. I think you will never say anything stupid. Just say what you really think about seriously and naturally so that you will be great! I think some warm tea can help:)

Thanks! I'm just worried because I have a narrow research focus and this is the only place that fits perfectly (I have other offers, but the fit is difficult). I've been expatriated in remote Africa for some time now and so I'm sort of out of it with Western Social Behavior. I keep thinking that somehow when we meet up in person, I'm going to do something so totally socially unacceptable, or so nervous that I make others nervous about me!!!

Take it as a really good sign that you will meet the other lab members. It would be more worrying if you didn't have the chance to talk to them (then the supervisor has something to hide).
If you go to a pub this will not be considered as a part of the interview, it is more likely an excuse for the lab to go out together. They might simply go out for birthdays, accepted papers or other social occasions. Don't panic.

It's a good sign to be invited to meet others in the lab. I doubt they will expect you to be brilliant, but they do want to see that you can be normally sociable. And it you explain that you are a still nervous from the interview, most of the lab will understand because they had an interview once also!
You have a really good chance of getting this PhD because the supervisor invited you without an interview, so go and enjoy yourself.