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

Other days

blanket fort

Blanket Fort Day
one

One Day
stud

Stud Day
eat what you want

Eat What You Want Day
self care

Self Care Day
lisp

Lisp Day
offer

Offer Day
camera

Camera Day
pampering

Pampering Day
comfy

Comfy Day