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

Other days

gallery

Gallery Day
embarrass your best friend

Embarrass Your Best Friend Day
first love

First Love Day
martini

Martini Day
stress awareness

Stress Awareness Day
my little pony

My Little Pony Day
cuddle up

Cuddle Up Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
nae nae

Nae Nae Day
tell ur crush you like them

Tell Ur Crush You Like Them Day