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

Other days

china

China Day
martini

Martini Day
raise awerness of zeus

Raise Awerness Of Zeus Day
hiv awareness

Hiv Awareness Day
prosecco

Prosecco Day
hannah

Hannah Day
stud

Stud Day
fiancee

Fiancee Day
bow tie

Bow Tie Day
ruby

Ruby Day