Oops, it doesn't look like 'museums are free all day' is a national day..

Other days

Hiv Awareness Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Prosecco Day

Self Appreciation Day

Ponytail Day

Fiancee Day

Cuddle Up Day

Donate Your Hair Day

Frozen Yogurt Day

Tell Ur Crush You Like Them Day