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

Other days

hannah

Hannah Day
donate your hair

Donate Your Hair Day
gum

Gum Day
promposal

Promposal Day
polyamory

Polyamory Day
boy friend

Boy Friend Day
bow tie

Bow Tie Day
lisp

Lisp Day
aloxolt

Aloxolt Day
pick me

Pick Me Day