Oops, it doesn't look like 'museum of natural history opened with much fanfare last day' is a national day..

Other days

Pampering Day

Lumpy Rug Day

Eat What You Want Day

African Immigrant And Refugee Hiv And Hep Awareness Day

My Little Pony Day

Stress Awareness Day

Stud Day

Ormille Day

Me Day

Camera Day