Anyway, this one is a social game for a large group of people (at least 20 or so), so maybe an icebreaker or at a conference or something.
First you decide upon three topics of factionalism, and four permitted values for each. So eg.
- Favourite colour – red, yellow, green, purple;
- Most inspiring Wizard of Oz character – Tin Woodman, Scarecrow, Cowardly Lion, Wizard;
- Best housebuilding material – timber, brick, concrete, steel frame.
Assign each player a random value from each category. So player A might be assigned Red, Scarecrow and Concrete; player B gets Purple, Wizard and Concrete; etc. Player A is then considered to be in the Red Faction, the Scarecrow Faction and the Concrete Faction, and so on.
Each player knows what Factions they are in (and has some sort of card or something on which they're recorded), but they aren't publicly visible. (They aren't secret, just not obvious.)
The game proceeds by the players mingling and chatting with one another in one-on-ones. In one such interaction, Player A approaches player B, they introduce themselves, and player A chooses one of their three Faction allegiances to enthuse about (eg. what a wonderful character the Scarecrow is, triumphing over his lack of brain). Player B listens respectfully but begs to differ, suggesting that the Wizard's ingenuity is truly admirable. Having established that they disagree, B chooses another Faction allegiance to raise, arguing that Purple is a colour of marked superiority. But A prefers Red.
A and B can now, if they both want to, agree to convince each other – ie. A will change from Red Faction to Purple Faction, and in return B will change from Wizard Faction to Scarecrow Faction. Or vice versa – as they mutually prefer. They mark these new values on their cards, and from now on must believe and argue them as vigorously as they did their initial positions.
A and B now separate, and each moves away to start a new conversation with other players (who meanwhile have been doing the same sort of thing, all over the room). As people convince and are convinced by each other, the number in each Faction will rise and fall. If it was purely random, it would stay fairly even, but my suspicion is that topics will usually tend to congregate towards one Faction or another.
The game continues with these free-flowing exchanges, until a predefined time limit has passed: then the organizers tot up how many members there now are of each Faction, and announce the results.
(Note that if you find yourself talking to someone who is already in your Faction for all three topics, or for two of the three, then you might as well bid them a cheery farewell and move on to someone else.)