The following from the Kuala Lumpur Hash House Harriers' charter still applies today:
To promote physical fitness among our members
To get rid of weekend hangovers
To acquire a good thirst and to satisfy it in beer
To persuade the older members that they are not as old as they feel
If you like beer, rude jokes and songs and you do not take yourself too seriously, this could be for you. We hash once a week, that is to say, we run or walk or crawl, a set course marked by a hare. As this is not a race but more a game that we play before we drink, competitive running is frowned upon. The hares (course markers) mark out a trail of flour, putting all sorts of traps and pitfalls in it, and usually we have a Drink Stop at some pub. At the end of the trail, this group of lunatics (and you can be one of us) will form a fraternal circle (led by the Religious Advisor), sing vulgar songs and come up with excuses for, and encourage their comrades to chug beer (like we need a reason)! After the ceremonies we have more beer and some food, and a good time in the company of our fellow hashers.
You understand that this is a totally unorganized, unsanctioned, unsafe, immature, irresponsible, and downright foolish thing to do. Yet, you choose to do it anyway on your own free will (Hell, you will even pay to do so). Yes, you are stupid! If you get hurt, it is your own damn fault.
If you want to find out more, check out our links page or Wikipedia. There you will find sites with articles on the history of hashing, beginners guides and much more that will give you a pretty good idea of what this is all about.