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

Other days

kiss a brunette

Kiss A Brunette Day
tulip

Tulip Day
ruby

Ruby Day
stud

Stud Day
cuddle up

Cuddle Up Day
mean girls

Mean Girls Day
buddy

Buddy Day
artists

Artists Day
stress awareness

Stress Awareness Day
brow

Brow Day