Do what you love, and do it in depth. Stretch yourself. Be creative. Take the activity up a notch or in new directions. Explore it. It isn’t about what you do so much as it is about the experience of challenging yourself and the growth, the journey/experience. Showing that challenge and growth, not just writing about it, makes a difference.
It’s unlikely you’ll guess correctly whether a college needs a harpist or a couple of clarinet players this year, or if it needs more football or more volleyball players. Hone your skills in activity you love, and you’re bound to go further than you could by doing something you don’t like nearly as much just to impress a random admissions officer somewhere.