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

Other days

ponytail

Ponytail Day
donate your hair

Donate Your Hair Day
camera

Camera Day
unicorn

Unicorn Day
eat what you want

Eat What You Want Day
pumpkin

Pumpkin Day
stud

Stud Day
slime

Slime Day
boy friend

Boy Friend Day
ruby

Ruby Day