Oops, it doesn't look like 'park or have her day' is a national day..

Other days

ride the wind

Ride The Wind Day
lumpy rug

Lumpy Rug Day
brow

Brow Day
tulip

Tulip Day
believe

Believe Day
youth

Youth Day
slime

Slime Day
prosecco

Prosecco Day
my little pony

My Little Pony Day
cuddle up

Cuddle Up Day