Oops, it doesn't look like 'flag high on australian flag day' is a national day..

Other days

artists

Artists Day

chocolate milkshake

Chocolate Milkshake Day

Me Day

ponytail

Ponytail Day

believe

Believe Day

ruby

Ruby Day

hiv awareness

Hiv Awareness Day

stress awareness

Stress Awareness Day

carpenters

Carpenters Day

azonto is acceptable

Azonto Is Acceptable Day