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

Other days

tulip

Tulip Day
eat what you want

Eat What You Want Day
one

One Day
gum

Gum Day
kiss a brunette

Kiss A Brunette Day
healing

Healing Day
stud

Stud Day
camera

Camera Day
pumpkin

Pumpkin Day
lisp

Lisp Day