Oops, it doesn't look like 'park plans special day' is a national day..

Other days

bow tie

Bow Tie Day
pick me

Pick Me Day
polyamory

Polyamory Day
boba

Boba Day
gum

Gum Day
law

Law Day
blanket fort

Blanket Fort Day
slime

Slime Day
buddy

Buddy Day
stud

Stud Day