I was given a design exercise to complete. They gave me a list of tasks/elements that needed to be addressed in an interface design. They liked my design. (I had applied for another position earlier in the year that I didn't get, so they already had met me and had my resume.) A week or two later, I was brought in for interviews. I interviewed with probably 12 different people, some 1 on 1, some 3 or 4 at a time. That lasted for about 4 hours (probably because I talked too much).
I have to say, it was the most thorough interview I've had. I was convinced that they understood exactly who I was and what could and couldn't do.
Over the next two weeks they were interviewing other candidates. About 2-3 weeks after my interview they scheduled a phone call with me. During the call they extended an offer. I started working a week later.