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

Other days

lumpy rug

Lumpy Rug Day
pampering

Pampering Day
ruby

Ruby Day
law

Law Day
youth

Youth Day
nae nae

Nae Nae Day
aloxolt

Aloxolt Day
bow tie

Bow Tie Day
gum

Gum Day
boy friend

Boy Friend Day