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

Other days

self appreciation

Self Appreciation Day
kiss a brunette

Kiss A Brunette Day
stud

Stud Day
offer

Offer Day
ruby

Ruby Day
tell a fairytale

Tell A Fairytale Day
ride the wind

Ride The Wind Day
prosecco

Prosecco Day
one

One Day
cursing

Cursing Day