Oops, it doesn't look like 'league side maidenhead on a day' is a national day..

Other days

martini

Martini Day
nae nae

Nae Nae Day
ruby

Ruby Day
hiv awareness

Hiv Awareness Day
bow tie

Bow Tie Day
tell ur crush you like them

Tell Ur Crush You Like Them Day
believe

Believe Day
cursing

Cursing Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
azonto is acceptable

Azonto Is Acceptable Day