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

Boba Day

Blanket Fort Day

Believe Day

Buddy Day

Appreciate Yaself A Lil Extra Day

Stress Awareness Day

Kiss A Brunette Day

Self Appreciation Day

Embarrass Your Best Friend Day

Youth Day