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

Other days

pumpkin

Pumpkin Day
embarrass your best friend

Embarrass Your Best Friend Day
singles

Singles Day
boy friend

Boy Friend Day
nae nae

Nae Nae Day
artists

Artists Day
brow

Brow Day
cuddle up

Cuddle Up Day
martini

Martini Day
offer

Offer Day