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

Other days

mean girls

Mean Girls Day
bounce

Bounce Day
one

One Day
bow tie

Bow Tie Day
book

Book Day
eat what you want

Eat What You Want Day
tell a fairytale

Tell A Fairytale Day
hoodie

Hoodie Day
unicorn

Unicorn Day
boy friend

Boy Friend Day