A competition where two people insult each other continously; the first person to back down, hesitate etc is the loser.
The usual insults revolve around physical flaws (look at yaw teeth, dey so yellow i don' needa put a light on at night) and clothing (yo, man, what make yaw sneakers?)
Thought to have started in Washington D.C. but there are variations all over the world, a particularly famous concentration being among young black people in London.
geeky schoolkid who wants to appear "with it": come on, man, there's a jone fest behind the gym building!
all geeky schoolkids who want to appear "with it" race around to the gym building, where a black stain has already gathered.