Recruiter visited my school and was accepting resumes. Decided to attend at the last minute and sort of just threw a resume together. A bunch of friends heard back and I was sure I had been denied, till a few days later I received an email asking me to schedule a phone interview. Phone interview was pretty basic, only 1 simple testing related problem. Rest of questions were more to gain a sense of my background and skills. Within a day of the phone interview I got an email saying I had bee recommended for a onsite interview. Lots of emails to book the trip, hotel, etc. A few days before interview, received an email saying the business division I was interviewing for. Flew down to Redmond (Microsoft covers everything and gives a ton of resources to ensure a pleasant visit). Interview day they pick you up from the hotel and take you to the building where your division is located. You spend most of the day in a room with a lot of other interns. There's 4 interviews, each 45 minutes. At each interview time an army of interviewers show up, one assigned for each candidate. During the interviews you are usually asked a question about yourself, followed by coding, followed by test cases. Within 24 hours received the results.

2 rounds: Phone interview then on Microsoft campus interview