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

Other days

bounce

Bounce Day
kiss a ginger

Kiss A Ginger Day
kale

Kale Day
nae nae

Nae Nae Day
youth

Youth Day
coffee

Coffee Day
tulip

Tulip Day
stud

Stud Day
brow

Brow Day
my little pony

My Little Pony Day