National Day Calendar, a private company in Mandan, North Dakota, set April 5 aside for National Nebraska Day. The observance began as part of a fifty-state series the company started in 2017.
The man who counts the days
National Day Calendar has belonged to Marlo Anderson since 2013. He got there by accident: in 2012 he went looking for where National Popcorn Day had come from, found no single place that answered the question, and started building one.
What he built is not a government office. Slate's 2025 profile describes an annual wall calendar as the backbone of the business, alongside branded merchandise and a television show. The company also invents holidays outright for paying clients, which it discloses.
The awkwardness sits at the center of the model and Slate names it: the days Anderson announces are not his property. Nobody owns National Selfie Day, in the same way nobody owns Thanksgiving. What the company has instead is the habit of being cited, which the piece describes as the media letting it become the de facto administrator of days like these.


