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

Other days

boba

Boba Day
bow tie

Bow Tie Day
eat what you want

Eat What You Want Day
stud

Stud Day
boy friend

Boy Friend Day
believe

Believe Day
girl friend

Girl Friend Day
youth

Youth Day
martini

Martini Day
pumpkin

Pumpkin Day