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

Other days

hoodie

Hoodie Day
law

Law Day
nae nae

Nae Nae Day
stress awareness

Stress Awareness Day
carpenters

Carpenters Day
kiss a ginger

Kiss A Ginger Day
cat girl

Cat Girl Day
boba

Boba Day
lash

Lash Day
bow tie

Bow Tie Day