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

Other days

special education

Special Education Day
comfy

Comfy Day
kiss a brunette

Kiss A Brunette Day
martini

Martini Day
cat girl

Cat Girl Day
brow

Brow Day
slime

Slime Day
kiss a ginger

Kiss A Ginger Day
one

One Day
boba

Boba Day