Passive Constructions are usually compared with its active voice equivalents. When passive voice is introduced, students want to see how passive voice works. The conversion from active voice to passive voice makes it clear how passive constructions are built.
This PowerPoint game-like grammar quiz covers the difference between active and passive voices. They need to find the agent and decide whether the sentence is in active or passive voice. The game-like structure is enhanced with some sound effects and a timer for fun time in class. I strongly recommend it to turn it into a grammar competition and make groups compete in it.