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

Other days

tulip

Tulip Day
ride the wind

Ride The Wind Day
hoodie

Hoodie Day
boy friend

Boy Friend Day
brow

Brow Day
stress awareness

Stress Awareness Day
bow tie

Bow Tie Day
girl friend

Girl Friend Day
ponytail

Ponytail Day
martini

Martini Day