AG contacted me to interview with them. Your first round is a case study as they want to see if you are able to comprehend how a consulting company works/thinks. If you are an engineer and use the internet, this should not be a problem.
Your second round interview consists of another case study, a behavioral, another behavioral but based on leadership, a chat with a new guy, and food with the guys up top. These are all rather simple but be prepared to offer a good reason of "why Acquity Group?". I was asked this in all 5 parts of the second round.
The tour showed 2 floors inside the Citi Group building in downtown chicago with the first looking like a cubical maze from office space and the second being a much smoother environment with all the cubical walls knocked down. Glancing around, it seems that there weren't too many people occupying these cubicals. I assume this is due to travel.