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

Other days

kale

Kale Day
frozen yogurt

Frozen Yogurt Day
azonto is acceptable

Azonto Is Acceptable Day
cat girl

Cat Girl Day
stud

Stud Day
stress awareness

Stress Awareness Day
pick me

Pick Me Day
hoodie

Hoodie Day
believe

Believe Day
lisp

Lisp Day