Oops, it doesn't look like 'posts on first day' is a national day..

Other days

martini

Martini Day
kale

Kale Day
cuddle up

Cuddle Up Day
slime

Slime Day
kiss a brunette

Kiss A Brunette Day
kiss a ginger

Kiss A Ginger Day
reading

Reading Day
boy friend

Boy Friend Day
ruby

Ruby Day
prosecco

Prosecco Day