Microsoft came to my college's career fair, and I dropped off my resume with them there after talking to the college recruiter for awhile. About a week later I had an on campus interview. The interview was a about 10 minutes of talking about myself and what I wanted to do, and then he asked me to code a question about strings in c.
After this they emailed me about to weeks later and asked me to come on site for the second round interview. They flew me up to Seattle all expenses paid, and put me up in a nice hotel. The actual second round was for me a series of 4 interviews. I was told there would be any number between 3-5 interviews depending on what they wanted to see.
The team I worked with seemed very laid back and relaxed. They didn't really seem to care whether I had the most correct answer or not as long as they could see what I was thinking. Overall it was a very positive experience.