I think I have been playing this for as long as I have been teaching. Doubt that I came up with it, but can’t remember where I stole it from and I have definitely made it my own, so I am claiming this one…
You ask questions to the students based on the lesson. Kids with correct answer get to go to the door. Depending on difficulty of the question they can take friends with them, or send people back to their seat. You can let them chose what they do or instruct them to save or send people back. Whoever is at the door at the end of the game gets to leave first. At any point you can swap everyone round so the seated students go to the door, and the ones standing go back to their seats.
It’s a great way to test student understanding, but equally a great way to build student confidence and social standing with their peer group. When less confident students get the correct answer, you can tell them to pick a number of students to take with them to the door which helps improve their status in the group. More importantly kids love it, especially when they get to send their friends back to their seats. This makes their peers even more determined to get the right answer. You will also see quickly who is sitting out of the game, perhaps because of lack of understanding or confidence so you can direct easier questions, or address their misconceptions later.
If your group start getting too excited and loud you can start adding extra rules like if anyone by the door talks during questioning, or shouting out, they have to go back to their seat.