I am very active in my fraternity: have been treasurer, vicepresident, philanthrophy chair, and scholarship chair
I also divide my time up with campus organizations like Tri-beta and SWCS in addition to the AED.
I do things like a camp for children with cancer, play intramural sports, been on the SGA senate and cabinet, and various things in the community.
But, most importantly I just did everything that interested me. Granted it looks like a lot, it really did not bog me down cause I enjoyed all of it. And thats what is important, is that you just have a good time in college.
Also, If the interviewer were to ask me about any of these things, I could talk about them for at least 15 mins. Some of the medical stuff for hours. Thats wants important, if you can express these to the people interviewing you.