In articles at Overcoming Bias and Less Wrong, the words "Blues" and "Greens" are often used to refer to two opposing political factions.
The terms come from the names of chariot racing teams, that differed in nothing but the team colors, but rivalry of whose fans sometimes reached the level of gang wars.1
Political factions usually identify with political positions, and use arguments as soldiers to defend their side. However, such dichotomies are often false dilemmas, which can be shown by presenting third options.