(plural Mischief Nights)
- (in the UK, Canada, and the US) A particular night during which young people play pranks and do mischief in their neighborhoods.
- (dated, originally) The night before May Day.
- (in the UK) The night before Bonfire Night.
- (in the US, where it has this name in Maryland, Delaware, Pennsylvania, New York, Massachusetts, Rhode Island, Connecticut and especially New Jersey) The night of the 30th to the 31st of October (the night before Halloween).