Oops, it doesn't look like 'organizer of the first earth day' is a national day..

Other days

brow

Brow Day
tulip

Tulip Day
bounce

Bounce Day
blanket fort

Blanket Fort Day
pumpkin

Pumpkin Day
boy friend

Boy Friend Day
one

One Day
fiancee

Fiancee Day
stud

Stud Day
polyamory

Polyamory Day