Basically come in and shoot the breeze for an hour. If you get interviewed by Caroline B. you'll get the job, don't worry. She is an idiot, you are smarter than her. She won't even ask about your background/work history. She didn't for me anyway, which I found to be staggeringly idiotic. I'm sure you could make your entire background up as it will not be a subject of conversation in the interview. I doubt they do background checks FYI.