So what are you into? Ok great, that’s exactly what you should look into. Chances are, at IU there is an organization or club that touches on that exact thing that you like. For me, I like salsa dancing Yes, there is a club for that. I have competed in a couple triathlons. Check, there is a running club, biking club, and swimming club (and team). Professionally, there are so many options. I am part of a student organization for those within my field of study. I am part of the Emissaries for Graduate Diversity. The opportunities to join an organization or almost limitless. Outside of the university there is a professional organization for just about every field in existence. I have yet to hear of a field that does not have a national or international organization for said field.
From personal experience, you will not have enough time to participate in every organization pertaining to your interests. They key is to select a couple and be active in those. Balance is important: you don’t want to pick to many and experience burn-out or exhaustion; you don’t want to pick to few and not have many experiences outside of coursework. 2-3 organizational affiliations seems to be healthy for any grad student…from what i can tell. For me, that has seemed to work pretty well.