How it works
For a technical breakdown of the method used to generate coordinates, see The Algorithm.
Every day an effectively random location in your area is selected - geohashing is about visiting these locations, that you might not have had a reason to visit otherwise. The world is an amazing place full of interesting people to meet and adventures to embark on.
Unless you can accurately predict the stock market down to the penny, you can't figure out what the coordinates will be ahead of time. You can get a weekday’s coordinates at about 9:30am ET, and on Friday you can get the coordinates for each day that weekend. There is no need to calculate coordinates by hand.
In cases when it is unwise to attempt to access the generated coordinates within a graticule, a recent coordinate may be substituted, or users may suggest their own alternate meetup location.
When visiting geohash locations, please respect the area you are visiting. Absolutely do not litter or otherwise disturb the natural integrity of the area. However, if possible, creating some kind of a marker out of nearby materials (i.e. cairn of stones, snow, blair-witch-style ‘stick figures’, etc.) is encouraged.
Sometimes you need to go above and beyond (or, perhaps, beneath and short of) the call of the GPS receiver to get to your hash. The achievements page lists recognized wins (and fails) of geohashing and corresponding awards. If you claim achievements, or just to have reached the coordinates, it is encouraged to provide some kind of "proof", such as a picture of the coordinates on your GPS display, and one of your Stupid Grin™.
Really Cool Expeditions
Sometimes a picture is insufficient to describe how seriously cool a geohashing expedition was. You may need a thousand words. Please contribute links to the Hall of Amazingness of “you have got to see this!” way cool expeditions that we might otherwise not hear about.
Great Geohashing Quotations
There are some things that can only be said while or about geohashing, incomprehensible to others but instantly recognizable to other geohashers. Here's where you can immortalize and laugh at the best Geohashing Quotes from expedition reports and the IRC channel.
Other Fun stuff
There are other little pages and projects that are kinda fun too. To save them getting lost in the depths of the wiki, they can be found here.