Well, if and when I can't ride as much, I guess I will step up the reading more; maybe do book groups or stuff at the library. I am a foodie, and we go out to eat a lot. The cooking thing is related.
I used to fill up a lot of time (in addition to working full time teaching at the gym part time, and teaching religious school), volunteering. I got burned out on that and now am very stingy with my time.
I enjoy just sitting and looking at the scenery during the time I am not in class, studying, working at my internship, or riding. After so many years of having no time, I don't want more hobbies to fill it up.