Oops, it doesn't look like 'cups of the day' is a national day..

Other days

gum

Gum Day
brow

Brow Day
my little pony

My Little Pony Day
nae nae

Nae Nae Day
hoodie

Hoodie Day
promposal

Promposal Day
lumpy rug

Lumpy Rug Day
lisp

Lisp Day
camera

Camera Day
first love

First Love Day