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

Other days

ruby

Ruby Day
believe

Believe Day
me

Me Day
pick me

Pick Me Day
lumpy rug

Lumpy Rug Day
eat what you want

Eat What You Want Day
blanket fort

Blanket Fort Day
buddy

Buddy Day
singles

Singles Day
martini

Martini Day