May 31st 2004 Share definition Flag The day the man with the smallest penis was born... Mr. Men. Also known as Mr. Men Day! Person 1: Hey, it's May 31st 2004, Keshav was born! Person 2: Oh, Keshav, as in Mr. Men? It's Mr. Men Day! May 31st 2004 by Brin Bib October 31, 2019 Get the May 31st 2004 mug.