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

Other days

pampering

Pampering Day
artists

Artists Day
ruby

Ruby Day
girl friend

Girl Friend Day
cuddle up

Cuddle Up Day
buddy

Buddy Day
frozen yogurt

Frozen Yogurt Day
gum

Gum Day
martini

Martini Day
donate your hair

Donate Your Hair Day