Oops, it doesn't look like 'left handed middle child day' is a national day..

Other days

brow

Brow Day
hoodie

Hoodie Day
bow tie

Bow Tie Day
lash

Lash Day
nae nae

Nae Nae Day
kiss a brunette

Kiss A Brunette Day
kale

Kale Day
girl friend

Girl Friend Day
ponytail

Ponytail Day
book

Book Day