What year are you? I'm assuming that you are just entering college next year, or maybe entering your second year? I'd recommend the following two things for your summer:
-- Buy a copy of "The Art of Electronics" by Horowitz and Hill, and read it cover-to-cover. It's a great introduction to electronics, from the basics through opamp circuits and digital electronics. With that background, you will be much more effective as an EE student.
-- Build a couple of electronics kits projects, and throughout your EE education, try to keep building projects on the side. Start with some basic projects, and progress through kits and projects that involve microcontrollers (uCs) and programming them in assembly language and C. If you build a few things on the side, you will have a much more practical approach to your schoolwork. I like to call it "learning to ask the right questions, both of your teachers and of yourself". You can get some good kits at Radio Shack, or at websites like this one:
http://www.transeltech.com/kits/kits1.html