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

Other days

get funky

Get Funky Day
artists

Artists Day
tell a fairytale

Tell A Fairytale Day
polyamory

Polyamory Day
my little pony

My Little Pony Day
lumpy rug

Lumpy Rug Day
pick me

Pick Me Day
ruby

Ruby Day
lisp

Lisp Day
cursing

Cursing Day