The process is as follows:
- Silently write down on sticky notes the major events that occurred
- Create a single timeline on a wall
- One by one, layout the notes in order of occurrence on the timeline
- Place positive events above the timeline and negative events below the timeline
- Discard duplicates
- Have one person walk through the final timeline
- One by one, rank the events on the timeline using dot voting
- Identify actions for the highest ranked events
- Rerun the time line with the actions and see what changes and if you get the desired outcome.
Adapted from: Putting the fun back in your retrospectives @ Agile2011