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

Other days

stud

Stud Day
gum

Gum Day
nae nae

Nae Nae Day
hoodie

Hoodie Day
donate your hair

Donate Your Hair Day
stress awareness

Stress Awareness Day
comfy

Comfy Day
get funky

Get Funky Day
lash

Lash Day
kale

Kale Day