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

Other days

book

Book Day
ask out your crush

Ask Out Your Crush Day
slime

Slime Day
blanket fort

Blanket Fort Day
offer

Offer Day
coffee

Coffee Day
healing

Healing Day
eat what you want

Eat What You Want Day
tulip

Tulip Day
singles

Singles Day