Oops, it doesn't look like 'Park And Zeus Cave day' is a national day..

Other days

kale

Kale Day
blanket fort

Blanket Fort Day
brow

Brow Day
youth

Youth Day
one

One Day
my little pony

My Little Pony Day
bubble bath

Bubble Bath Day
singles

Singles Day
cuddle up

Cuddle Up Day
artists

Artists Day