They flew me out to NYC and put me up in the Eurostar Hotel on Wall Street. The interview was the next day and it was two one-on-one interviews followed by lunch, then a Q&A with some of the other candidates and a VP. The interview went over some basic CS concepts (polymorphism, etc) then went into Flex specifics - binding, process flow, the 'elastic racetrack'. I'm self-taught through experience so I hadn't known some of answers and actually came out of it knowing more than I went in. It was a very relaxed atmosphere throughout though.