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

Other days

youth

Youth Day
get funky

Get Funky Day
coffee

Coffee Day
self appreciation

Self Appreciation Day
ponytail

Ponytail Day
kiss a brunette

Kiss A Brunette Day
bow tie

Bow Tie Day
cuddle up

Cuddle Up Day
book

Book Day
bounce

Bounce Day