The objective is to line everyone up in order of birthday. Oldest at one end, youngest at the other.
Simply ask your group to do this, but there is one catch - they cannot talk. They can use their hands or whatever. A very simple game but one that works well for workshops, and ice breakers.
You can use this game to select teams. When you have the line formed, ask alternate people to step forward. This gives you two groups of random people with a good spread of ages.
To make it more of a challenge you can get people standing on a line of chairs, or outside on a beam or log which they must not come off.
Click this animated image!