This is more challenging than it sounds…
Ask the group to stand in a circle. Set a numeric goal for the group to reach (start with 15 or so). Explain to the group that once the activity begins, participants can only say a number – no side conversations or strategies!
Once the leader says, “Go,” someone (whoever decides to start) in the group starts by saying, “One,” followed by someone different (whoever decides to speak next) calling out, “two,” and so one until the group reaches its goal.
The challenge is that if more than one person calls out a number at the same time, the group needs to start over at the beginning. Since there is not a set order, this happens quite a lot!
As a variation, you can give the group a time limit (say 10 minutes) to reach the highest possible number.