The process took 1 day. I interviewed at Boston Consulting Group (Boston, MA) in Dec 2010
Interview
Nice interviewers - they were very professional and helpful throughout the process, and even took the time to give me feedback over the phone after I did not receive an offer. It seemed very casual, deceptively so. One was particularly laid back during the case portion of the interview - he told me I wouldn't need to take notes (I did, however).
Interview questions [1]
Question 1
A software company is interested in setting up a cloud storage system - should it enter the market and how?
Very intense case interviews, usually run by a project leader or senior analyst. They will ask you a lot of questions and follow up questions. Be prepared! Most of them are nice, not all, so be ready for a tough hour.
Case study and personal experiences. They give you a lot of material to prepare with, it's a lot about structured thinking. Make sure you prepare the case study structures and know what experiences you can use to answer.
They were looking for someone who would be willing to jump in to multiple roles, not just the one advertised and the pay did not reflect my expectations for the level of work they wanted.