There's an old Christmas tradition that my friends and I follow every year, which has long been the preserve of the prep school/public school set in other countries...
It is essentially a bar crawl wherein 12 drinking establishments are visited in sucession and at least one drink is consumed in each. The ceremony requires that each participant wear a Christmas jumper - the worse the better! Gaudy reindeer knits, several sizes too small and with unexplainable holes and stains are by far the most revered!
Some like to demand that participants also don a festive headpiece but not so with my old school chums. The core rules are simple - Christmas jumpers are absolutely necessary. 12 bars and 12 drinks must be ticked off. Each participant is allowed to introduce a new rule as the evening continues which may be as ridiculous as they like (popular rules include: "no showing your teeth when smiling or talking", "no pointing", "no referring to other participants by their names", drinks must be consumed upside down", "right hands must remain in pockets all evening" and so on). Failure to comply with a rule results in a drinking related forefeit!
The night ends in disaster.
Sometimes a football or rugby ball is introduced and must be passed between participants without dropping (a British/Irish game often referred to as pub rugby). You're not allowed to pass to the person who passed to you and thus the last person in possession of the ball must accept a forefeit.
Furthermore the game is sometimes merged with another drinking game classic: Chinos. I may or may not explain the rules of this game at another stage! Suffice it to say that all participants must wear chinos/khakis and will need to adequately demonstrate their need to use the toilet to other participants before being allowed to do so by displaying their intention on their chinos.