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

Other days

kale

Kale Day
gum

Gum Day
unicorn

Unicorn Day
nae nae

Nae Nae Day
comfy

Comfy Day
cat girl

Cat Girl Day
boy friend

Boy Friend Day
eat what you want

Eat What You Want Day
kiss a ginger

Kiss A Ginger Day
mean girls

Mean Girls Day