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

Other days

frozen yogurt

Frozen Yogurt Day
slime

Slime Day
boy friend

Boy Friend Day
hiv awareness

Hiv Awareness Day
special education

Special Education Day
prescription drug take back

Prescription Drug Take Back Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day
bubble bath

Bubble Bath Day
ride the wind

Ride The Wind Day
kiss a brunette

Kiss A Brunette Day