Oops, it doesn't look like 'at chepstow the day' is a national day..

Other days

bonang

Bonang Day
bow tie

Bow Tie Day
latina equal pay

Latina Equal Pay Day
boba

Boba Day
promposal

Promposal Day
lisp

Lisp Day
slime

Slime Day
ruby

Ruby Day
unicorn

Unicorn Day
book

Book Day