Oops, it doesn't look like 'post every single picture or video you have of you and all your friends on snapchat day' is a national day..

Other days

Nail Polish Day

Ormille Day

Stress Awareness Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Kiss A Brunette Day

China Day

Camera Day

Azonto Is Acceptable Day

Polyamory Day

Ruby Day