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

Other days

nail polish

Nail Polish Day
get funky

Get Funky Day
kale

Kale Day
bounce

Bounce Day
believe

Believe Day
hoodie

Hoodie Day
boba

Boba Day
ask out your crush

Ask Out Your Crush Day
bow tie

Bow Tie Day
book

Book Day