3 rounds of for interviewing.
The first round consisted of an hour long conversation that served as a casual litmus test to see if I had enough experience, and was someone they wanted to work with. It was a great opportunity to ask questions about responsibilities, level of skill required, and to check out the sweet office.
The second round was a little longer, closer to two hours, and a little more technical. Basically "How would you implement this?", "Tell us about some of the projects you have worked on.", and similar questions. Also another culture check, featured different people, and not just .NET developers.
The third round was a 7-hour code day that was broken up with a 1-hour lunch. The challenge was agreed upon by myself and the tester on the spot. More of a "show us what you got". Followed by a code review and questions both ways following the demo.
Pretty intense, but an awesome place to work, and the interview process helps to make sure that everyone hired is a good fit culturally and talent wise.
