My initial resume was handed in by a Professor that I used to do work for. He had also been the referrer of the past two interns beforehand. Therefore, I was offered an initial interview. I did sub-par in my eyes, but later (over a month) received an email requesting a phone call. I spoke with my potential supervisor, and was later scheduled to come in for a rotational interview, meeting most of the group. I ran through some technical questions, which were limited in subject matter due to my education level at the time. I did well on overall and blended with the group, so I was later offered a position for the summer, and it was a great experience.
Easy - Questions were repetitive and simple, will be harder for more experienced engineers.