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

Other days

brow

Brow Day
blanket fort

Blanket Fort Day
bubble bath

Bubble Bath Day
my little pony

My Little Pony Day
bonang

Bonang Day
tulip

Tulip Day
stud

Stud Day
cuddle up

Cuddle Up Day
kiss a ginger

Kiss A Ginger Day
aloxolt

Aloxolt Day