From SA Mafia Wiki
Lights Out is a style of game where the Town can execute multiple times in a single game day. Typically what happens is the town must execute before the deadline, killing the player but withholding their cardflip. Each successful execution extends the deadline slightly, typically with each extension shorter than the last. When the town no-hangs by a deadline, the day ends, everyone executed is cardflipped, and night begins.
Lights Out can be a very dynamic game, but it can also give too much power to the town by allowing them to execute multiple scummy candidates all at once.