Oops, it doesn't look like 'hero pon him earth day' is a national day..

Other days

slime

Slime Day
china

China Day
lumpy rug

Lumpy Rug Day
boyfriend

Boyfriend Day
book

Book Day
boba

Boba Day
brow

Brow Day
kiss a ginger

Kiss A Ginger Day
tell a fairytale

Tell A Fairytale Day
tulip

Tulip Day