I applied through website, had two phone interviews, one technical and the other HR followed by a day long 6 round interview at the TR office in Minneapolis. On the interview day, there were 6 candidates for the summer and full time positions combined. We were initially given a group case study which we presented to a group of senior Technology managers, followed by 3 rounds of one to one technical and academic interviews( Since this was a Phd position, they had an "academic" interview as well) and a round of white paper presentation based on a topic I received by email 24 hours before the interview. The final round was an HR interview from their London office.