Oops, it doesn't look like 'shelter adoption day' is a national day..

Other days

lisp

Lisp Day
blanket fort

Blanket Fort Day
lash

Lash Day
bounce

Bounce Day
boy friend

Boy Friend Day
offer

Offer Day
singles

Singles Day
gum

Gum Day
lost sock memorial

Lost Sock Memorial Day
cuddle up

Cuddle Up Day