Oops, it doesn't look like 'p i z z a day' is a national day..

Other days

youth

Youth Day
camera

Camera Day
stud

Stud Day
hot chocolate

Hot Chocolate Day
comfy

Comfy Day
slime

Slime Day
kiss a ginger

Kiss A Ginger Day
hannah

Hannah Day
coffee

Coffee Day
carpenters

Carpenters Day