Oops, it doesn't look like 'museums shut for second museums are shut for a second day' is a national day..

Other days

Polyamory Day

Gum Day

Nae Nae Day

Stress Awareness Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Book Day

Chocolate Milkshake Day

Buddy Day

Prescription Drug Take Back Day

Raise Awerness Of Zeus Day