Investment Banking Summer Analyst

The interview process was fairly simple. I had been in contact with an alumni who works at the office and was a 2nd year analyst there for a couple of months. She ended up referring me to whoever was running the recruiting. Later, I was called by an associate to schedule my interview for a certain day over the phone (I live on the East Coast and the office I was interviewing for was located on the West Coast). At the time of the interview, two associates called and were on the phone with me, each asking some questions. The interview, 30 minutes long, was primarily technical, no fit questions with the exception of the typical "Walk me through your resume." I ended up getting two questions incorrect and was not offered a chance to go to their superday the next week.
The interview itself was fairly difficult. They would ask a relatively simple question, but it would be followed up with a couple of more detailed follow-up questions. I would suggest getting to know your technicals very well if you are interviewing here. Also, my contact at the firm had said that the interview had become more technical than in years past, so I don't know if that will differ from other interview insights you've seen/heard.
Throughout the process the people I met were really nice and very helpful. I only rate my interview experience as negative simply because I did not do well, that is not an indictment on the people at the firm and their organization process, but rather my performance throughout the interview process.