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

Other days

unicorn

Unicorn Day
bow tie

Bow Tie Day
brow

Brow Day
kale

Kale Day
girl friend

Girl Friend Day
youth

Youth Day
nae nae

Nae Nae Day
mean girls

Mean Girls Day
get funky

Get Funky Day
promposal

Promposal Day