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

Other days

china

China Day
unicorn

Unicorn Day
blanket fort

Blanket Fort Day
self appreciation

Self Appreciation Day
lisp

Lisp Day
gum

Gum Day
one

One Day
brow

Brow Day
latina equal pay

Latina Equal Pay Day
artists

Artists Day