I saw Ultimate Software at our Job Fair. I was taken away by the fact that they were very impressed with my leadership skills on my resume (not a very common thing to hear as a software engineer). Then I was invited to their dinner and later on I got an email to set up a phone interview. The phone interview was pretty typical, not too hard. Required a decent knowledge of OOP and some basic principles. Then I went to the onsite interview which was 4 technical interviews back to back. The first had to do with basic programming, it was a bit more OOP than I expected. The next had to do with Test Engineering. The next was a more traditional technical interview with typical interview questions (data structures, efficiency, etc). The last was technical but a bit behavioral as well. Then we had lunch, and then that was it. We went back and forth on the phone after that, and it did take me a while to get the actual offer as they were still interviewing candidates. It may be important to note that I was a grad student when I went in for the interviews. I've heard the questions differ greatly for undergrads depending on the classes you've taken.