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

Other days

reading

Reading Day
eat what you want

Eat What You Want Day
law

Law Day
mean girls

Mean Girls Day
bow tie

Bow Tie Day
one

One Day
blanket fort

Blanket Fort Day
polyamory

Polyamory Day
self care

Self Care Day
me

Me Day