All peoples in the world celebrate and have always celebrated the winter solstice. We Westerners have had various pagan midwinter traditions that were later 'transformed' by the Church into Christmas.
Well, the Chinese obviously still have their midwinter festival, which is called the Dōngzhì (冬至) Festival. On this day, all members of the clan must assemble at the Ancestral Hall and worship their ancestors. Failing to do so will cause penalties to one's Allegiance score in most Chinese religions (see the rule book). Specially consecrated tāngyuán (湯圓, glutinous rice flour balls) are eaten during the ceremony. These consecrated tāngyuán serve as protective talismans to keep evil spirits from coming close to whomever has eaten them. In gaming terms, no guǐ-monster can come closer than 10m to the person for 2D6 days.
This year, the Dōngzhì Festival fell on 22 December. Sorry for having been late with the relevant post!