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

Other days

ruby

Ruby Day

reading

Reading Day

lost sock memorial

Lost Sock Memorial Day

boy friend

Boy Friend Day

Emoji Day

pumpkin

Pumpkin Day

nae nae

Nae Nae Day

girl friend

Girl Friend Day

first love

First Love Day

tell a fairytale

Tell A Fairytale Day