Oops, it doesn't look like 'be a dumbass day' is a national day..

Other days

china

China Day
nail polish

Nail Polish Day
one

One Day
boy friend

Boy Friend Day
youth

Youth Day
fiancee

Fiancee Day
raise awerness of zeus

Raise Awerness Of Zeus Day
bow tie

Bow Tie Day
me

Me Day
pick me

Pick Me Day