The Southern Poverty Law Center has some great resources on teaching tolerance. One exercise uses a carefully chosen falsehood to demonstrate how easily the truth can be overwhelmed by irrationality and emotion: divide a class into teams, have the teams compete against each other in the performance of an arbitrary task, but tell students that each team contains a traitor who will secretly attempt to sabotage his or her team’s efforts. The fact that no traitors actually exist is only revealed afterward, in the debriefing discussion. The exercise can serve as a simple but effective way of getting students to examine trust, stereotyping, and the effects of false assumptions.
Before incorporating this or any other such exercise into one’s classroom repertoire, it’s wise to think hard about the ethical and methodological complications that can potentially arise, especially when using simulations that relate to race and ethnic identity.
I disagree on the SPLC; it has to be one of the least “tolerant” organizations I have encountered. It is tolerant as long as you hold their views.