You do not need something interesting. Add maybe one or two more activities/clubs/community volunteering that you ENJOY. Maybe pick up a hobby or something. You already have plenty of things and you are only a sophomore. More opportunities will arise throughout your years in undergrad. Just don't go overboard and lose that GPA.
Running is a great activity to keep in shape so I'd continue doing it, but I feel like a majority of applicants are runners/weight lifters so it won't make or break your application.
I do have a job at a national company teaching ACT and SAT classes to high schoolers, and I'm wondering if that would be seen as good leadership experience . . .