Oops, it doesn't look like 'river clean up day' is a national day..

Other days

frozen yogurt

Frozen Yogurt Day
kiss a ginger

Kiss A Ginger Day
cat girl

Cat Girl Day
buddy

Buddy Day
lumpy rug

Lumpy Rug Day
offer

Offer Day
one

One Day
get funky

Get Funky Day
lash

Lash Day
ride the wind

Ride The Wind Day