I'd never heard of Mischief Night before, but then it seems to be local to northern England.
From the BBC:
Depending on where you live, it lands sometime around Halloween and Bonfire Night. And opinions vary on whether it is a chance for harmless fun or an excuse for anti-social behaviour.
Like many native traditions, its exact origins are unknown, but Mischief Night is thought to date from the 1700s when a custom of Lawless Hours or Days prevailed in Britain...
Since the 1950s, Mischief Night appears to have died out in all areas of the UK except northern England, and it is not at all clear why.
What is known is that it was exported to the United States, and recently re-imported as trick or treat, now popular across the UK.
Comments
Bonfires? We leave that for the English, and Detroit.
Oh, and Bonfire Night is the 'modern' name. It used to be called Guy Fawkes night, and the bonfire was to burn an effigy of Guy Fawkes. Some places still do this.