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

Other days

ride the wind

Ride The Wind Day
frozen yogurt

Frozen Yogurt Day
law

Law Day
my little pony

My Little Pony Day
bounce

Bounce Day
brow

Brow Day
nae nae

Nae Nae Day
one

One Day
get funky

Get Funky Day
blanket fort

Blanket Fort Day