Oops, it doesn't look like 'bands day' is a national day..

Other days

hoodie

Hoodie Day
azonto is acceptable

Azonto Is Acceptable Day
bow tie

Bow Tie Day
prosecco

Prosecco Day
hannah

Hannah Day
blanket fort

Blanket Fort Day
lash

Lash Day
donate your hair

Donate Your Hair Day
ormille

Ormille Day
kale

Kale Day