How much is an action item worth to the team? Source:
Hang up the list of possible actions. Draw a column next to it, titled 'Importance (in $)'. The team gets to spend 100 (virtual) dollars on the action items. The more important it is to them, the more they should spend. Make it more fun by bringing paper money from a board game such as Monopoly.
Let them agree on prices. Consider the 2 or 3 highest amount action items as chosen.
Let team members appreciate each other and end positively Source:
Agile Retrospectives who took it from 'The Satir Model: Family Therapy and Beyond'
Start by giving a sincere appreciation of one of the participants. It can be anything they contributed: help to the team or you, a solved problem, ...Then invite others and wait for someone to work up the nerve. Close, when no one has talked for a minute.