As a Psych student I have learned about some really interesting experiments and human processes over the past 3 years. One of the most interesting courses was Social Psychology where we were taught all about money and it's detrimental effect on happiness and the psychological factors behind our destruction of the environment. Anyway, social conflict was one of the phenomena we studied and over the course of learning about it we learned of the Robbers Cave Experiment done by Sherif and colleagues in 1961.
Social Conflict - The Robbers Cave Experiment
They created and resolved conflict between two groups of young boys in a summer camp style setting using techniques such as co-operation for the benefit of everyone! Really interesting experiment to read