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

Other days

bubble bath

Bubble Bath Day
ride the wind

Ride The Wind Day
lumpy rug

Lumpy Rug Day
my little pony

My Little Pony Day
china

China Day
ormille

Ormille Day
buddy

Buddy Day
kale

Kale Day
prosecco

Prosecco Day
bow tie

Bow Tie Day