Oops, it doesn't look like 'rest yo lip flap day' is a national day..

Other days

hoodie

Hoodie Day
ruby

Ruby Day
camera

Camera Day
lisp

Lisp Day
stress awareness

Stress Awareness Day
gum

Gum Day
buddy

Buddy Day
pampering

Pampering Day
kiss a ginger

Kiss A Ginger Day
frozen yogurt

Frozen Yogurt Day