Historical role playing games at my college are becoming more and more popular as a teaching method within the History and Classics departments. I, for example, am currently doing a roleplay game of the Simla Conference in India in 1945. My roommate did a role-play of Athens after the Peloponnesian War and how to rebuild their government. The outcomes of these games almost never are the same as what actual happened, but it is fun to consider what the outcomes could have been.
As a pedagogical method, these games are one of the best. They are fun and engaging with the students, which I think should be a high priority. But they also encourage students to engage with the historical materials and with each other. Forming alliances can only happen when there are willing participants in the class and only with knowledge backing their alliance. It would be ridiculous to have Gandhi, who promoted non-violence, to ally with the biggest army in India, that invades every chance they can get. By needed to have knowledge in order to play the game, people are compelled to go out of their way to learn and study in order to make good political decisions and to achieve bonuses within the game.
There are also roles for all sorts of students. Students with more confidence may want to have a more in-depth role whereas people with less confidence may take a role that has less stipulations on it. Not to say that all roles are not important. Anyone can shift the focus of the game into a certain person or groups favor.
The last great thing about these types of games is that you can change the outcome of whatever historical event you are role-playing. Democracies could be created where none existed, violence could no longer exist, societies without prejudice could be created. These types of games allow for future generations to truly learn from the mistakes of history and create a new better society in the future.