A word of warning, first, just because a certain sport may or may not be safe for indoor play, you still want to have plenty of space! Even if youre using a foam basketball, theres still a possibility of knocking valuable things right over. Ideally, indoor sports should be restricted to a room free of fragile things, and with plenty of room for a little bit of running and jumping. Of course, then again, ideally you want to be playing sports outside.