There were a total of 5 interviews. The first one was over the phone and was relatively simple. An asian girl interviewed me for about a half hour and asked me some basic questions like how I would go about testing a keyboard and given 8 marbles that weigh the same and one that weighs more, find the one that weighs more in 2 weighs with a balance scale. After that I was invited to 4 onsite interviews at their Cambridge office. I was flown out via plane and given a hotel, all expenses covered (food, taxi, etc.). The people were very nice and accommodating, and we talked about my resume, how I would solve and test certain problems, and I ate lunch with one of my interviewers and we talked about how we got into Computer Science and our experiences so far learned and adaptive to being a CS major. Overall I had an extremely fun time interviewing at Microsoft.