My students and I had a lot of fun with a review game this year - in fact, they often asked if we could play! I used it successfully with grade 8-12 students, but I think you could easily play this activity with kids as young as 7 or 8.
In the subjects I teach there is often a lot of vocabulary that students need to learn in order to understand the larger concepts. So when it comes time to do our unit review, I write down vocabulary words on a sticky note and stick a note to each student's back. Then, either as a small group sitting together, or a large class working together, they must ask each other questions to determine what word they have stuck to their back. It's the same idea as the game Headbanz, but without the fancy headband! Students can only ask questions that can be answered with a "yes" or "no".
This game can be modified for several different subjects - students could try to guess important events in a Social Studies, famous people, an element on the periodic table, characters in a novel, a number...
I was blown away by how much my students loved this game! They began to challenge each other to get the word in 5 questions or less, they wanted me to play with them and took great joy in trying to stump me, and they eventually played all on their own. I gave out several sticky note pads and they would decide on words for each other!
Super easy, super fun and super effective!!