After a couple of pre-screening calls, both of which excited me about the company culture (very people-oriented both internally and externally), I went in for a multi-part panel interview process. There were several small groups, as well as a lunch break. Overall the questioning was tough but fair. You can really tell folks get coached internally for hiring, since their questions tend to follow the formula "describe a time that (x) happened", the answer to which would be a lead in to a discussion about a technique or personality trait. They played it very poker face the whole time, so it wasn't always easy to gauge the temperature of the room. Overall, a nerve-wracking but positive experience. Also, they've got really nice offices.