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

Other days

lisp

Lisp Day
bow tie

Bow Tie Day
hoodie

Hoodie Day
gum

Gum Day
brow

Brow Day
raise awerness of zeus

Raise Awerness Of Zeus Day
boba

Boba Day
boy friend

Boy Friend Day
believe

Believe Day
mean girls

Mean Girls Day