For my interview I met with the whole office (about 10 people) - they put me in a room, and 2-4 people would come through at a time to chat, usu a half-hr or so. I met with the big boss, some science guys, and some developers. Nice staff, on the young side, no one over 40. They were dressed business casual to just plain casual. They asked me what projects I'd worked on, then they explained what they did. They did a lot of the talking. To do well in the interview, be able to describe projects you've done, and maybe read up on their site and be able to converse with them about the company's work. Was not stressful, no brainteasers, no whiteboard in the room. I was asked a few technical questions, but nothing like they're trying to trick you or anything. All in all, was low-key, more of a test of if personalities would mesh ok.