Oops, it doesn't look like 'slack liberation day' is a national day..

Other days

ormille

Ormille Day
ruby

Ruby Day
blanket fort

Blanket Fort Day
stud

Stud Day
gum

Gum Day
bow tie

Bow Tie Day
lumpy rug

Lumpy Rug Day
artists

Artists Day
youth

Youth Day
martini

Martini Day