I wonder if there's any other person who spends more time pondering this crucial question, one of the most imporant decisions of my imagined life - if I were a cute girl, what kind of club would I join? That's a really, really tough one. It kept me awake throughout countless nights, just think about all these possibilites!
Okay, I'm beggining to exaggerate here but I really spent quite a while thinking about it. And I don't think I ever reached any satisfying conclusion. Mahjongg sounds like fun. Jazz sounds even better if they'd be willing to accept a complete newbie (of course they would be, we would all be cute 2D girls).
Sports clubs look nice to me but that's my perspective as a guy. A classy girl wouldn't engage in such an indecent activity!
Those basketballs in the pic are the size of handballs (especially if you take the fact that Japanese are smaller on average into account). Seriously, I have a pretty large hand and I can barely palm a basketball. Hell, even handballs are harder to palm than you'd think (well, plaming is easy enough but try to make some fast movements without losing the grip) - even pros use a special glue-like substance on the tips of their fingers to improve their grip.
TL;DR QUALITY WARNING