Gobstones is a game involving stones played
something like marbles, in which the stones spit disgusting liquid at the
opposing player when they lose a point. There are Gobstone clubs at Hogwarts
(OP17) and also an International Gobstones League (DP) Many of the kids at
Hogwarts have a set of Gobstones and it's played fairly regularly (CS10, PA16,
GF20). Harry was tempted to buy a solid gold set in Diagon Alley (PA4). The
offices of the Official Gobstones Club are in the Department of Games and Sports
on level seven of the Ministry of Magic (OP7).
The picture showed a skinny girl of around fifteen.
She was not pretty; she looked simultaneously cross and sullen, with heavy brows
and a long, pallic face. Underneath the photograph was the caption: Eileen Prince,
Captain of the Hogwarts Gobstones Team. (25- The Seer Overheard)