Why Lesson Planet?
What would your class do if a police officer arrested a student in class? This is exactly the anticipatory set that gets students engaged in a unit on the legal system. The plan is to get the officer to simulate an arrest, and then guest speak to start the unit. After 2-3 weeks of case-study instruction, a mock-trial is held for the original "culprit," with roles played by local attorneys, and a student-jury rendering a decision. Consider having students play all the roles.