I liken the interview to Pop Idol - there are two rounds.
In the first round it's the interviewers telling you about the company, the job role etc etc then a general get to know you and then group activities, where, like any group activity, you are being judged not on the outcome but how you work well in a team environment.
Then it's go and have a coffee and get all nervous before they call your names and split you into two groups (the Pop Idol bit) and you'll either be told get your coat or congrats you're through to the one-to-one (or is it two-to-one now) where you'll have your chance to shine like the Virgin star you are.
Just keep smiling and thinking about customer service.
Good luck!