Westvleteren 12 has a bit of an international reputation of being the best beer in the world. It's constantly rated as the no. 1 beer by sites like Beeradvocate and ratebeer (8 and Blonde have ranked highly too), and given this attention, the Wall Street Journal wrote a piece on the monastery in 2007. Westvleteren 12 is brewed by monks in the Trappist Abbey of Saint Sixtus Westvleteren in Belgium.
It is extremely difficult to obtain due to its very limited production and distribution. It's only available at two official selling points: the drive-up sales window at the abbey and at the In De Vrede (In the Peace) café across the street. The current production is 4750 hl annually (for comparison, an average microbrewery in the United States produces 18000 hl annually). The bottles have no labels – all the legally required information is written on the bottle caps.
Getting the beer today means calling the monks at the St. Sixtus Abbey ahead of time and making an appointment, driving to the monastery and then buying a maximum of two crates per person once a month. Its rarity has certainly contributed to its mystique worldwide, and the monks have no intention of increasing production despite demand. In an article in the Belgian newspaper De Morgen, Brother Joris explained that they "brew to live, but don't live to brew." The money they make is just enough to sustain their lives at the monastery (well, monks are also allowed to drink the Blonde ale with their meals). Anyone who buys the beer agrees to not resell it. The monks want their beers to only be available in the area of West Flanders for local and private consumption. But that doesn't mean a grey market for the beer hasn't emerged.
From Wikipedia: "Despite the popularity, the monks of St Sixtus have continued to decline almost all interview and visit requests, and have not enjoyed all of the attention they have received. Non-monastic visitors to the abbey are usually turned away, instead being directed to the visitor's centre opposite where there is information about the abbey and brewery. They have stated a desire to live a peaceful monastic life, and find the resulting interruptions quite intrusive."
The Saint Sixtus Abbey is one of seven Trappist monasteries that produces beer. Only these seven breweries are allowed to label their beer with the Authentic Trappist Product logo that indicates compliance to the rules of the International Trappist Association.