Internships, real world experience?

I am currently working on my third internship, and while my resume looks impressive with all this "experience" I've had, I wonder, am I really experienced in the field? In a perfect world, in each internship I would work under my boss, and he would allow me to help out with as much as possible, so when I am completed with the internship, I would feel comfortable doing such tasks on my own. I would love to say this is the has been the case in my experiences, however I cannot say this. I have found that I am GREAT at entering data into excel, can probably say the alphabet backwards, and have conquered the mail merger. I often find myself passing the hours in my lonely cube doing undesirable busy work that my "co-workers" do not wish to do themselves. I understand I am only an intern, and this is the work I am supposed to do, but I wish I would get the opportunity to work on more important tasks, tasks that actually matter and will help me in the future. I have been assertive seeking these types of tasks, however I am always stuck back in my cube doing yet another cumbersome task. I wonder, when I graduate, will I be able to preform as well as my resume makes me look?