Usually refers to a teenage boy, used in the North Part of Argentina (Santiago del Estero), comes from the angient indian language "Quechua". Also used as an exclamation word, to enphasize a desire, desagreement, opinion, thought, etc. "Changuito" its a form of the same word that applies to small boys/kids. Nevertheless its a way of getting someones attention when you dont know their name, like the "Oi", "Che", "Hey", etc.
"Eh chango que calor que tengo!" "Hey man im so hot!"
"Ese chango es muy buena onda" "That guy is very cool"
"Eh chango estas mal de la cabeza!" "Hey dude you are so fucked up!"
Often used in Argentina to describe people who wear dark clothes, make-up, that could easily be goths, some sort of punks, etc. They usually go out in big groups (more than 3 people) at night, generally "depressed", and with the thought that they dont belong to society. It also doesnt aply to the sort of music they´re interested, only to the way they look/dress. Its common among them to only relate between "Darkies", not very sociable.
"I went to a Rasmus concert... It was filled with Darkies"