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

Other days

artists

Artists Day
healing

Healing Day
brow

Brow Day
eat what you want

Eat What You Want Day
martini

Martini Day
my little pony

My Little Pony Day
get funky

Get Funky Day
kale

Kale Day
slime

Slime Day
mean girls

Mean Girls Day