Oops, it doesn't look like 'drink served at any time of the day' is a national day..

Other days

Brow Day

My Little Pony Day

Ride The Wind Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Chocolate Milkshake Day

Kiss A Brunette Day

Pick Me Day

Donate Your Hair Day

Bow Tie Day

Boyfriend Day