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

Other days

tulip

Tulip Day
lumpy rug

Lumpy Rug Day
pick me

Pick Me Day
nae nae

Nae Nae Day
slime

Slime Day
lisp

Lisp Day
bonang

Bonang Day
blanket fort

Blanket Fort Day
artists

Artists Day
latina equal pay

Latina Equal Pay Day