So, what the heck is the hash? It's got nothing to do with coffee shops; it's a worldwide 'drinking club with a running problem.'
It started back in 1938 in Kuala Lumpur and has spread throughout the globe since then. The original club formed to do a paper chase run (if you're Dutch, think 'speurtocht') followed by a session at their local club, nicknamed The Hash House. In other words, their purpose was to build up a good thirst, and then to satisfy it. You can read a more complete history of the hash at http://harrier.net/presskit/shistory.html.
What to expect
The rules of the hash are simple: there are none. The hares set the trail, either a few hours or the day before or five or ten minutes before the hash starts. The pack tries to follow the trial, solving the various challenges along the way and often stopping for a drink stop halfway through. The hares use various markings on the trail to tell the pack where to go, most often using chalk, flour, or sawdust.