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

Other days

artists

Artists Day
fiancee

Fiancee Day
tulip

Tulip Day
tell a fairytale

Tell A Fairytale Day
mean girls

Mean Girls Day
bow tie

Bow Tie Day
blanket fort

Blanket Fort Day
kale

Kale Day
kiss a brunette

Kiss A Brunette Day
ruby

Ruby Day