It's such a natural fit that I can't believe I didn't see it before. Cats are furry, tipped with razor sharp claws and teeth, and generally grumpy. They are clearly the perfect substitute for an athletic ball of any shape or size.
And thus, the Sports Balls Replaced with Cats tumblr was born.
It wasn't my genius idea, but something tells me that my cat would object* if I attempted to dribble him towards the net.
*And by "object," I mean "rip my face off."
Please, please tweet me if you can think of an athletic situation where a cat wouldn't rip your face off @bookoisseur.