I started by submitting a resume and some other information, then was contacted about doing a personality test (a bit strange, but not particularly difficult) and an SAT-style exam (most of it wasn't very hard, though I struggled with the last few coding questions). I then had a phone interview, which was very laid-back and easy. It was mostly questions about my resume, my thoughts and questions on the position, and an attempt to gauge my interest. I then was flown out to Madison with all expenses covered and spent the night in a nice hotel. The onsite interview was also really relaxed. They spent just as much time wooing the applicants as they did attempting to find if they were the right fit. It's a busy day and you'll meet lots of people, but it's a lot of fun. Just be yourself and try to be relaxed; they're looking for people who will fit the position and the company, not people who are prepared with all the "right" answers. The facilities really are excellent and there are a lot of great people there.