Snowball

From the original public announcement:

Snowball is a variant rules system based on 'The Pool' and 'The Questing Beast,' as well as other variants on the same.

Snowball was created to roughly mimic and emulate the style of story-creation seen in the movie "Memento," starting with the last scene and moving back towards the first in discrete intervals. However, there's no reason that Snowball couldn't be modified for any other construction, including forward-moving stories, and stories whose scenes are entirely out of order….the basic Snowball construction assumes the ending scene first, with everything else following after.

Like its progenitor games, Snowball is a role-playing game system geared towards narrative collaboration between a GM and one or more players. Characters in Snowball are not defined by a list of carefully balanced attributes that match up to some objective standard. Instead, they are defined with a series of traits whose only rating is, effectively, how important such traits are to the story.