Oops, it doesn't look like 'hawaiian shirt and khaki shorts day' is a national day..

Other days

Stud Day

Nae Nae Day

Raise Awerness Of Zeus Day

Stress Awareness Day

Boba Day

Carpenters Day

Tulip Day

Lisp Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Slime Day