I commissioned into the Army by ROTC, so the interview process was in two phases. The 1st phase is at the school, where current and retired officers and NCOs put you into situations, and evaluate your leadership potential, while learning Army Leadership Model, and skills such as physical fitness (the Army way), land navigation, the five paragraph operations order, and small unit tactics. The 2nd phase is at the Leadership Development and Assessment Course, or LDAC, at Joint Base Lewis McChord (JBLM). During that time, you will go through a "mini" basic training with students throughout the country. You will be evaluated in the aspects mentioned above and more, but the kicker with the situational exercises, or STX Lanes, is to evaluate your leadership with a group that you have are not familiar with (or they try...I knew some of the people in my group from other FTXs).
Disclaimer: For anyone that reads this, there is a lot more, such as the process of tabulating which branch you will get, but this is pretty much the gist. Also, this is circa 2010, so it is best to ask the Professor of Military Science, or the ROTC recruiter, what are the requirements for joining the Army at this route. Also, I did not go through Basic Combat Training, so this is pointless. However, if you do go through ROTC, it would benefit you to go to BCT, as you learn most of the Soldier skills introduced in ROTC, and you can earn more experience about the Army as cadet reservist. There is more money as well, but that is not the