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

Other days

reading

Reading Day
first love

First Love Day
unicorn

Unicorn Day
youth

Youth Day
nae nae

Nae Nae Day
bow tie

Bow Tie Day
self appreciation

Self Appreciation Day
promposal

Promposal Day
tulip

Tulip Day
slime

Slime Day