Oops, it doesn't look like 'Double Entendre day' is a national day..

Other days

youth

Youth Day
bow tie

Bow Tie Day
slime

Slime Day
bubble bath

Bubble Bath Day
tulip

Tulip Day
lost sock memorial

Lost Sock Memorial Day
coffee

Coffee Day
ormille

Ormille Day
brow

Brow Day
kiss a ginger

Kiss A Ginger Day