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

Other days

me

Me Day
boba

Boba Day
believe

Believe Day
blanket fort

Blanket Fort Day
pick me

Pick Me Day
donate your hair

Donate Your Hair Day
slime

Slime Day
bow tie

Bow Tie Day
hoodie

Hoodie Day
boy friend

Boy Friend Day