What do you enjoy doing in your free time?
The interviewer is simply trying to get to know you better. The best answer to this question will show that you have passions outside of the classroom. The question allows you to show that you are well rounded. Within reason, it doesn’t much matter what you do in your free time as long as you do something.
Your transcript will show that you are a good student. Your answer to this question will show that you are also someone who has diverse interests that will enrich the campus community.