Glühwein is most common at German Christmas markets. Each town will have its own mug design for the annual Christmas market, and each year the design is new. You pay for the glühwein as well as a deposit on the mug. Then you can return the mug or keep it for your collection. Glühwein is really easy to make at home, and it makes a fun addition to a cozy winter evening. Don't use an expensive dry red wine, but do use a wine that you would be happy to drink plain.