When something has 'gone pear-shaped', it means something has gone wrong or not according to plan.
My barbeque has gone pear-shaped - nobody has bothered to turn up.
A obsessive yet mysterious pastime engaged by London Underground addicts.
Usually reffered to as a game, Oyster Card skimming usually involves L.U. addicts around the age of 15-17 who 'borrow' their parents' Oyster Card and 'touching in and out' at Amersham Station at the end of the Metropolitan Line.
The game begins at any nomniated station between two or more players and the aim of the game is to reach Amersham Station by any means possible, but 'touching in' on the Oyster Card reader so that a time is recorded on the station's computer. The game ends when all players arrive at Amersham. The winner is the one with the fastest time.
The loser gets left behind on the platform to catch the next coming train and must join the others post haste at another nominated station.
"Jack went Oyster Card skimming and beat Jane..."