Oops, it doesn't look like 'stadium set up day' is a national day..

Other days

one

One Day
carpenters

Carpenters Day
lisp

Lisp Day
boy friend

Boy Friend Day
tell a fairytale

Tell A Fairytale Day
bow tie

Bow Tie Day
reading

Reading Day
frozen yogurt

Frozen Yogurt Day
brow

Brow Day
singles

Singles Day