Initial phone interview with HR, phone interview with the office you'll be working at, quick phone call about onsite interview, then the onsite interview. I am doing my onsite interview tomorrow so I can't give insight on that yet. The phone interviews went well, the people are very nice and make you feel comfortable. Laid back, low pressure. The first phone call is to talk about the job description and to see if you're still interested, then the second is with the office you'll be working with, in my case 2 people. Both 30 minute conversations. They just want to learn more about you and see what you're interested in so they can see where you can fit in and grow within the company.
Onsite interview is half a day, 7 thirty minute interviews with separate people (all one on one). 2 technical interviews, but no tests or riddles/puzzles.