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

Other days

slime

Slime Day
kiss a ginger

Kiss A Ginger Day
unicorn

Unicorn Day
my little pony

My Little Pony Day
blanket fort

Blanket Fort Day
camera

Camera Day
ponytail

Ponytail Day
brow

Brow Day
hot chocolate

Hot Chocolate Day
tulip

Tulip Day