A commemorative day established on the 11th of January because, if you consider a "1" as a person, it looks as if 3 people are playing UNO!
Can't find anywhere the actual reasoning behind setting it on this day, but if I were to guess, it's because "uno" is "one" in Spanish, and putting a commemorative day on the 1st of January would not be a good idea because of new year's so the 11th of January would be the next best thing.Looks like I'm already at UNO, huh~?
You guys are worse at this than I thought~