This one has been a hit for many classes. It is a simple team again, split your class into two teams and give each team a castle. Ask the team a set of questions, if they are correct they can come to the board and press their respective press cannon to fire a cat at their opposing teams castle. Each firing of the cannon WILL knock a piece of the opposing team's castle off. The winning team is the team with the largest, remaining castle.
OK, so the cat's trajectory is set (even my favourite tool of PowerPoint has its limits) but younger students will be captivated by the chances of missing and by what they might hit! It works really well for young students I have yet to try with older students, it might be a bit patronising for them.