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

Other days

slime

Slime Day
pick me

Pick Me Day
donate your hair

Donate Your Hair Day
prosecco

Prosecco Day
offer

Offer Day
law

Law Day
my little pony

My Little Pony Day
believe

Believe Day
frozen yogurt

Frozen Yogurt Day
boy friend

Boy Friend Day