Oops, it doesn't look like 'car seat check day' is a national day..

Other days

book

Book Day
kale

Kale Day
tell a fairytale

Tell A Fairytale Day
china

China Day
boy friend

Boy Friend Day
bubble bath

Bubble Bath Day
polyamory

Polyamory Day
law

Law Day
donate your hair

Donate Your Hair Day
stud

Stud Day