Oops, it doesn't look like 'wear a mask wear a mask day' is a national day..

Other days

one

One Day
gallery

Gallery Day
stud

Stud Day
kiss a ginger

Kiss A Ginger Day
law

Law Day
lumpy rug

Lumpy Rug Day
tulip

Tulip Day
fiancee

Fiancee Day
cat girl

Cat Girl Day
offer

Offer Day