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

Other days

stud

Stud Day
ormille

Ormille Day
hoodie

Hoodie Day
unicorn

Unicorn Day
boy friend

Boy Friend Day
singles

Singles Day
slime

Slime Day
reading

Reading Day
azonto is acceptable

Azonto Is Acceptable Day
blanket fort

Blanket Fort Day