October 23

National mono day. The day Kim Namjoon aka RM of the nation's top boyband, BTS, released his 2nd mixtape titled Mono for free because he is a humble king whi just wants to share his emotions with the world through music with no benefit other than making others feel happy

Person a: hey bro did you know that today is national mono day
Person b: wtf is a mono?
Person a: its RM's 2nd mixtape. Yeah he released this treasure on October 23, 2018
Person b: oh worm?lemme hear something from it
Person a: *plays uhgood*
Person b: damn bro this shit slaps, lemme go download the whole mixtape

Mono is a part of the holy trinity of mixtapes along with Agust d and Hopeworld.