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

Other days

artists

Artists Day
youth

Youth Day
hoodie

Hoodie Day
boy friend

Boy Friend Day
lumpy rug

Lumpy Rug Day
my little pony

My Little Pony Day
girl friend

Girl Friend Day
unicorn

Unicorn Day
book

Book Day
brow

Brow Day