For example, Gail Z. Martin's December 9, 2015 post on world-building. (see http://www.magicalwords.net/really-i-mean-it/world-building-with-holidays/
Adding the layer of Holidays to your world can help define the values of your world, what they spend money on, and how they celebrate.
WRITING EXERCISE - After reviewing the above blog, create a fictional holiday for your world and/or work-in-progress.
My present work-in-progress, Cons of Romance, is set in contemporary America and actually has some world-building based on holidays. A lot of conventions cluster about holidays, because the long weekends allow people to take time off. I tried to tie my fictional conventions to real American holidays, which made added an interesting twist for my world-building.
The first convention is located in Maryland during March. I will come back to it.
The second convention, "GearFest," is set in North Carolina during June and is only a two-day convention because it doesn't fall on a holiday weekend. I specifically wanted this to be a short convention.
The third convention, "Tea Party," is set over the July 4th weekend and is located in Boston.
The fourth convention, "WyvernCon", is located in September over the Labor Day weekend and runs nearly five days.
Again all conventions are fictional and created specifically for this romance novel.
Back to the first convention. I had decided the convention started life on the main character's, Tara Miller, college campus and was tied to a holiday in Maryland. I wanted the convention to happen before June but after the weather started to get warm. Something that wouldn't interfere with finals but warm enough people wouldn't get snowed in. Low and behold Maryland Day is March 25th. Thus my fictional "ConButtony" (a Cross Buttony appears on the distinctive flag of Maryland) was born.
YOUR TURN - Comment below about your use of holidays in a work-in-progress or, if you are a reader, a book you enjoyed specific for the holidays such as Hogfather by Terry Pratchett.