One and Done! (inspired by a Hanasawa Skype game, critiqued by LlamaFluff, Faraday, BBmolla, and KittyMo)
Basic premise:
All players have a one-shot PR. Scum get an advantage in selecting the first role and the member of the team to receive it and in influencing which of the eleven are left out of the game via eliminating one. The remaining players are then randomly assigned one role each from the remaining pool of nine, with the last unused role discarded.
Scum killing mechanic:
Scum get access to one-shot {kill, poison, treestump, arson, PGO} for killing purposes. Only one used per night. Theoretically the arsenal would refill if all the methods were consumed over the course of the game.
Kill is straightforward.
Poison is exactly one night delayed; target is not informed.
Treestump lets the person keep posting but no longer voting or using an unspent PR shot.
Arsonist is minimum one-day-night cycle delayed. Once primed, any surviving Mafia can ignite him at any time, day or night.
PGO is one-shot. Scum arming himself takes the place of a killing action that night and is used starting that night on the first person to target him for the rest of the game.
List of available one-shot PRs:
roleblocker, JK (protects against kill, arson), doctor (protects against kill, poison), paramedic (protects against poison, arson), tracker, self-watcher, neighborizer, commuter, gladiator, hider, back-up