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

Other days

carpenters

Carpenters Day
kale

Kale Day
stud

Stud Day
donate your hair

Donate Your Hair Day
unicorn

Unicorn Day
pick me

Pick Me Day
bubble bath

Bubble Bath Day
boba

Boba Day
my little pony

My Little Pony Day
girl friend

Girl Friend Day