Oops, it doesn't look like 'assembly elections held the same day' is a national day..

Other days

coffee

Coffee Day

blanket fort

Blanket Fort Day

frozen yogurt

Frozen Yogurt Day

Me Day

raise awerness of zeus

Raise Awerness Of Zeus Day

martini

Martini Day

bow tie

Bow Tie Day

bounce

Bounce Day

my little pony

My Little Pony Day

lash

Lash Day