As I progressed through my later years in high school, and now into college, the chatter about getting internships and "meaningful" summer jobs has gotten gradually louder and louder to the point at which now, I am probably asked about my work in every conversation I have. In truth, an internship is probably not the most important activity you will do all summer, especially as you progress through high school. The most important activity you will do is what means most to you- something that will help you develop as a human being, something that you will enjoy doing, and something that means more to you than a line on your resume. Colleges are accepting you as a person, not your resume as a piece of paper.
This is not to say that internships are not a way to "get an edge" in the college application process. Students who can come to college having done research or worked in a laboratory or corporate setting certainly are more comfortable going into the laboratory settings that are so prevalent in college. However, this issue is not the be-all-end-all that it seems.
For instance, my brother, who is a rising junior at Langley High School, has what I think is the perfect job for him this summer- in a bike shop. Having always been interested in motors, cars, and anything automobile, he is doing what he loves to do. Sure, he is not using vials, droppers, microscopes, or lasers, but this is an experience that he will not forget. So if you apply to internships and they do not work out, do not fret. Instead, look to the activity that you are most interested in doing, and try to apply that in a real-world setting.
My last reason for not worrying about a summer internship, that applies directly to the college application process: Remember, when you are writing your essays, you are not going to be writing about working in a lab for the summer. You are going to be writing about what you love, an experience that helped you learn, or something that is important to you.