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

Other days

pampering

Pampering Day
lash

Lash Day
kiss a brunette

Kiss A Brunette Day
tulip

Tulip Day
lost sock memorial

Lost Sock Memorial Day
book

Book Day
unicorn

Unicorn Day
ruby

Ruby Day
gallery

Gallery Day
kiss a ginger

Kiss A Ginger Day