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

Other days

self appreciation

Self Appreciation Day
donate your hair

Donate Your Hair Day
frozen yogurt

Frozen Yogurt Day
comfy

Comfy Day
offer

Offer Day
boba

Boba Day
mean girls

Mean Girls Day
law

Law Day
nae nae

Nae Nae Day
coffee

Coffee Day