Only a few of the following examples are actually ready-to-run in an undergraduate classroom, but they will provide inspiration and materials for your own role-playing exercises. Many of the scenarios, characters, and assignments need a few added details, which will enable you to tailor them to your course.
Earth System Topics
Jurassic Park Debate part of Pedagogy in Action:Library:Role Playing:Examples
This role-playing exercise casts students as scientific specialists, assigned to a group either supporting or opposing the cloning of dinosaurs. Each group researches and presents its argument.