Oops, it doesn't look like 'nengi n ninjas day' is a national day..

Other days

artists

Artists Day
latina equal pay

Latina Equal Pay Day
bow tie

Bow Tie Day
unicorn

Unicorn Day
fiancee

Fiancee Day
emoji

Emoji Day
kiss a ginger

Kiss A Ginger Day
gum

Gum Day
girl friend

Girl Friend Day
lisp

Lisp Day