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

Other days

lisp

Lisp Day
cuddle up

Cuddle Up Day
pampering

Pampering Day
first love

First Love Day
believe

Believe Day
artists

Artists Day
kiss a brunette

Kiss A Brunette Day
ruby

Ruby Day
my little pony

My Little Pony Day
boba

Boba Day