Oops, it doesn't look like 'msm day' is a national day..

Other days

ruby

Ruby Day
pumpkin

Pumpkin Day
first love

First Love Day
kiss a brunette

Kiss A Brunette Day
self care

Self Care Day
carpenters

Carpenters Day
frozen yogurt

Frozen Yogurt Day
boy friend

Boy Friend Day
slime

Slime Day
camera

Camera Day