Oops, it doesn't look like 'mourningflag will fly at half mast day' is a national day..

Other days

Book Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Raise Awerness Of Zeus Day

Kiss A Ginger Day

Martini Day

Blanket Fort Day

Ride The Wind Day

Frozen Yogurt Day

Kiss A Brunette Day

Girl Friend Day