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

Other days

bow tie

Bow Tie Day
ruby

Ruby Day
bubble bath

Bubble Bath Day
comfy

Comfy Day
girl friend

Girl Friend Day
blanket fort

Blanket Fort Day
gum

Gum Day
self appreciation

Self Appreciation Day
nae nae

Nae Nae Day
book

Book Day