"What?!?" you might be thinking. "I haven't even finalized my spring break plans yet!" Well, spots for summer programs fill quickly, and if you want to participate in one (not that you have to) - now is the time to apply. Many colleges and university sponsor summer academic programs. You can get a taste of college life, perhaps earn some college credit, improve your English, and make new friends. There are so many subjects to choose, from fine arts to dance, from behavioral neuroscience to journalism.
If an organized academic program isn't your thing, you could also: 1) volunteer, 2) travel (and perhaps visit a school that you are considering at the same time), 3) read, 4) try something new, 5) teach someone something, 6) find a job, and 7) stay active in one of your interests, whether it be sports or the trombone. Some of your summer activities may even end up becoming the topic of your college essays!
You have 1,680 hours of summer (roughly 10 weeks, and there are a 168 hours a week), so think about how you want to spend your time. Time management isn't just about saving time, but filling your life with activities that are fun, that help you learn more about yourself, and help you to become a better person.
Of course, there are problem some demands of your summer already set in place, such as a family vacation. If you are going to be a senior next year, I'd also recommend working on your college essay and/or art portfolio, researching schools, contacting the schools that you are interested in, and even visiting them if you can. If you are going to be a junior, you might consider preparing for the ACT or SAT. Just don't spend all your time on these college prep activities, playing video games, watching TV, or chatting on Facebook. Again, colleges and universities want to see that you are making an effort to be fun and interesting, learn more about yourself, and become a better person.
Consider perhaps making a list of things that you'd like to do, a list of your summer dreams, whether it's picnicking or having a sleepover with your friend. Then, you can take your list of dream activities, and then match that up with things that you might have to do over the summer. Take a look at your calendar and see how you can make some of those dreams a reality. That way by the end of the summer, you won't wonder where the time went and you can feel a sense of pride and satisfaction in achieving the summer of your dreams!