Hi muffinman23 and snoopypoo,
For many (myself to a limited extent), summer research is a piece of flare on their medical school applications. Since you're not applying to medical school, summer should be the time for you to be thinking about what you want to do with your MD degree.
The basic dichotomy is choosing between working in the clinical setting or conducting laboratory research. If you enjoy the former, lookup research or volunteering opportunities that will place you into patient care environments. Establishing an early relationship with Doctors Without Borders, for example, would be useful if you intend to pursue that route after medical school.
If you intend to conduct medical research, as is my objective, definitely pursue in-depth research opportunities now. Research is more art and luck than science because breakthrough are not made overnight. Moreover, there are so many different avenues of research that you want to make sure that you're doing something you enjoy. Since you are both freshmen, many on-campus laboratories may take you immediately because you'll be around for so long. However, some labs may require specific knowledge that you have yet to obtain.