Preparation: A few hours
Playing: 60 - 120 minutes, depending on your team size
First of all take a flipchart paper (or something of at least similar size - depending on your team size you might need a larger sheet of paper, you will understand why later on) and draw a large christmas tree. Draw it as large as you can and don't forget the star on the top, after all you want the tree to look nice:
Now draw some small candles and christmas baubles in 2 colors. Draw one candle and 2 baubles for every team member. If you're lazy you can draw one candle and one bauble in each color and then copy it a few times (that's what I did ;-)
Once you have your candles and baubles finished, draw a present and a christmas sock for every team member and write their names on it. In order to keep the presents and socks individual you might want to not copy them ;-)
Cut out the candles, baubles, presents and socks. After that create a matrix putting the socks on the left of the tree and the presents under the tree:
Last part of preparation is to buy some cookies for the retrospective itself :-)
How to playGive everyone a candle. Set the timer to 5 minutes and ask "What does motivate me getting up and going to work?". Everyone should write some words about the question on the candle (answers could be: I love our team, the current project is awesome, etc.). When the time is up everyone in turn glues her/his candle on the tree where her/his name crosses itself and says a few words about it. A glue stick might come in handy ;-)
Give everyone 2 baubles for every other team member. Set the timer to 10 minutes and ask them to write something about every team member. On one bauble they should answer the question "What did I like most about working with you?" (answer could be something like "I really liked pair programming with you") on the other "What do I hope I'll be able to be doing together with you next year?" (answer could be something like "I know you're really good at test driven development, so I hope you could teach me how to do it, at best while pair programming").
When you're done filling out the baubles, everyone in turn gets their presents. Let's assume you are the first to get your presents. Everyone in the team tells you what they wrote about you on their baubles and glue them at the corresponding positions in the tree-matrix (there are 2 for every combination). Once you have received all your presents, say a few words about how you feel and continue with the next person in your team.
Once you're finished, your tree should look like this: