From YahooNews:

‘Assassins’ patrol London’s streets with water guns in role-playing game

LONDON (AFP) - Londoners have begun a city-wide role-playing game where people roam the capital to shoot each other with water pistols as police warned that contestants might be committing criminal offences.
 
“StreetWars” has already taken place in New York, Vancouver, San Francisco, Los Angeles and Vienna, and on their website, tournament organisers describe it as: “A three week long, 24/7, watergun assassination tournament.”

As part of the game, participants are handed a manila envelope containing the details of their “target”, including their name, home and work addresses, along with a picture, and are assigned with the task of “assassinating” them with a watergun.

Upon being “killed”, the person who has just been eliminated from the game hands details of their target to the successful “assassin”.

(more here)