National 'No National Day' day.
A day where all of urbandictionary's made up national days are rendered moot.
A completely normal day.
Ex.
Person 1: "Hey, guess what? It's May 3rd, urbandictionary says it's National Rai-"
Person 2: "Shut the FUCK up, I'm tired of seeing screenshots of this goddamn site on my socials. It's 'No National Day' day today."