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

Other days

brow

Brow Day
tell a fairytale

Tell A Fairytale Day
lumpy rug

Lumpy Rug Day
bow tie

Bow Tie Day
stud

Stud Day
hiv awareness

Hiv Awareness Day
self care

Self Care Day
bubble bath

Bubble Bath Day
cat girl

Cat Girl Day
lisp

Lisp Day