I applied online, and I received a phone call two days later for an interview two days after that. I was told that it was a group interview, and that I would not have to bring anything. Because of that, and the fact that the online application did not actually have an option to do so, I opted not to bring a resume as it seemed to be low priority.
The staff seemed casual. In my interview group of five, three were dressed casually, and the fourth and I were dressed semi-casually. It was unclear to me what was most appropriate, but I probably could have gotten away with nice casual. The interview itself was rather laid back and straightforward, and it took place in the store itself.
The service manager went through the history and the values of the company, during which he would occasionally integrate questions to the group. They ranged from personal questions such as "What is your schedule like?" and "Why did you pick Chipotle?" to questions that tested one's knowledge of the Chipotle philosophy such as "What does food with integrity mean?" Some questions were just thrown out there, while others were specifically directed from person to person in an orderly way, making sure to give everyone an opportunity to answer.
We were told afterwards that if they were interested, they would call us for a second interview. I did not receive a phone call and it has been 7 days since. I've called once during that time period, hoping to check to see if I was still in the running or not (as the timetable for callbacks was not mentioned, and I have no idea how many first-stage interviews are being conducted); the person I spoke to couldn't answer and simply took my name down and mentioned again, that I'd receive another call if they were interested.