Oops, it doesn't look like 'camp tshirt day' is a national day..

Other days

martini

Martini Day
bow tie

Bow Tie Day
tulip

Tulip Day
blanket fort

Blanket Fort Day
emoji

Emoji Day
comfy

Comfy Day
cuddle up

Cuddle Up Day
kiss a ginger

Kiss A Ginger Day
self care

Self Care Day
bubble bath

Bubble Bath Day