Met Microsoft through a career fair at school in spring. I applied for an SDET intern position, did well at the on campus interview, but then was told that all positions for the summer had filled up. I was then flown out for an interview in Seattle in the fall. At the Microsoft HQ, I was run through a series of four interviews with various managers in the XBOX team. I ended up blanking in two of the interviews, so I didn't receive an offer. None of the questions were especially hard, I would just advise that you are well rested for the interview.