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

Other days

law

Law Day
tell a fairytale

Tell A Fairytale Day
martini

Martini Day
frozen yogurt

Frozen Yogurt Day
nail polish

Nail Polish Day
ruby

Ruby Day
offer

Offer Day
cat girl

Cat Girl Day
ride the wind

Ride The Wind Day
slime

Slime Day