Fireworks over the castle on The Mound
This is all Wikipedia gave me (not much more of a help, except to discover that it only became a bank holiday two years ago!): "St. Andrew's Day is the feast day of Saint Andrew. It is celebrated on 30 November. Saint Andrew is the patron saint of Scotland, and St. Andrew's Day is Scotland's official national day (although Burns' Night is more widely-observed). In 2006, the Scottish Parliament designated the St. Andrew's Day as an official bank holiday."