In other wild days of youth news, in a world quite like pre-Rebirth DC's, Timothy Drake-Wayne is encouraged by his adoptive father to develop some sort of silly overly public persona, lest people notice that there are *two* hypercompetent young adults with an overly developed sense of responsibility in Gotham, and deduce his secret identity (which, by the way, is Bruce No, of course I'm not influenced by any traumatic childhood experience linked to a favorite character who happened to be a masked vigilante hiding his identity behind the mast of a useless fop Wayne's main worry vis-a-vis secret identities, never mind that Tim figured his identity through a wholly unrelated kind of clue).
Anyway, Tim Drake, never one to miss an opportunity to enhance his persona as an enthusiastic geek among civilians, allies, and enemies alike (not to mention, *be* the enthusiastic geek he actually is, disguising it as a disguise), decides to go into the world of competitive yo-yo play:
Every one of his age peers, plus every former Robin and above half of the cumulative roster of the Titans will keep mocking him about it forever (perhaps item #7 in the Reasons I'm Tempted to Establish a Totalitarian Cyber-utopia in Gotham list Tim keeps in a little telepath-proof box in his mind), but Bruce is impressed. He has to alternate between faking clumsiness and being specially dense in order to compensate for the extreme sports he has to publicly engage in to cover how obviously trained he is, but Tim can actually show some reasonable dexterity and agility in his civilian life without endangering his cover. No matter what physical feat somebody might catch him doing, he'll shrug it off to his training, and everybody will both believe him and continue to find him utterly harmless and not a little bit silly, because, let's face it, he's a competitive yo-yo player. Plus, it's something that can be modified into some forms of useful training (add sharp edges to the yo-yos, work under increased and/or unstable gravitational fields, etc), so it's not as complete a waste of time as showing up to parties he's paying for and would pay far more not to attend, and distracting himself by Sherlock-scanning everybody until the sheer density of infidelities and petty crimes gives him a headache.
It's sheer genius.