I think bowling, and golf are games. IMO, sports are competitions where it's you against someone else, and you each have the ability to directly influence your opponet. In bowling, you put up your best score and can only hope it's good enough. Same for golf. Tennis, your opponet makes a great shot, but you still have a chance to make a great play of your own. Basketball, Baseball, Football, Hockey, etc...
As far as ESPN showing bowling, they also show the National Spelling Bee.