Robin could hit a sparrow through the neck from a half mile away, that's what the kids always said. He could hit a specific shingle on your roof, could send a rock sailing through a paper plate if you held it on the other end of a football field. It was what he did, that and skateboarding. His parents were as proud as two people without a clue could be. They treated him much the same as his sisters, though Robin couldn't walk two steps without being challenged to chuck something.
His sisters - who were really not his sisters at all, but regarded themselves as such - watched with a dry, why-can't-you-be-good-at-something-useful look. They themselves weren't slouches either; Sophie Smith was regarded up and down her elementary school as something of a genius, and Jean Smith wasn't much good at anything, though it was generally assumed that she was going someplace.
The two girls had lived with Robin ever since his parents had seen the burning, tumbling remains of the Smith household and then, subsequently, the will that their friends had left behind. It had been settled without much thought; Robin's parents already loved the Smith girls like their own and the two girls went over to their house often enough that it only seemed natural that they should slip in. And they settled well enough.

"Goddamn, I don't CARE if you think that you can hit that tree. I KNOW you can hit that tree."
"Betcha five dollars."
"Listen, I spent my entire twelfth year of life bankrupt because of you. I'm done. Maybe Sophie'll take you up on your offer." Robin snorted.
"Dude, I'm preying on the weak here. Your sister wouldn't take the odds unless I promised to hit the moon."
"So glad I'm the staggering, gimpy antelope."
"Mhm." Robin bit his lip, the picture of concentration. He paused precisely three seconds to take a deep breath, as was his custom, and then he launched the rock.
"Show off."
"Everyone encourages me!"