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

Other days

kale

Kale Day
one

One Day
self appreciation

Self Appreciation Day
camera

Camera Day
offer

Offer Day
ruby

Ruby Day
prosecco

Prosecco Day
nae nae

Nae Nae Day
cuddle up

Cuddle Up Day
coffee

Coffee Day