I was contacted for an on campus interview with BCG through my school's standard career services system. The first round interview was on campus and was comprised of 2 case interviews. Each case was done in a separate room with a Consultant (post-MBA) from the firm. Most of my interviewers had been at the firm for about a year. I was contacted about a final round interview within 48 hours of my first interview. At this point they would discuss what potential offices you might want to work in, and eventually decide which office you'd prefer to interview for. The final round was in the specific office I wanted to work in, in this case New York. The final round is comprised of 3 case interviews with Principals or Partners. I received my offer the same evening.