I have been using this game since I picked it up from one of the teachers during my first year of training.
For this game, the class needs to be ability grouped. Each group has to stand up and call out the answer to differentiated questions. If they are the first to answer correctly, they get to shoot someone on their team. They have to sit down. This continues until there is only one person left in that group (they sit down waiting for the final).
The next group does the same, and so on, until there are 5/6 children who have won a round. The final can then take place.
The overall winner can get a prize / house points etc.
This game can be a general mental maths game or a subject-specific one. It can also involve a lot of strategy… who is the best person to get out in their group?