A great lesson idea stems from Jenna Krambeck at Elkhorn Ridge Middle School in Elkhorn, NE. (You can visit her site here: http://elkhornbltf.wikispaces.com/ )
Dueling with Math Snowballs, now she is a reading teacher at Elkhorn so I have adapted this lesson from her. You start with a simple snowball fight. Students write down math problems on a half sheet or full sheet of paper and students fling their paper across the room. For more math snowball information check it out here.
To put this in perspective, students are in groups and it is their job to solve the problem. First team with 5 points wins.
The game proceeds as a student from a particular group walks up and picks up a piece of paper and challenges a group to solve a particular problem. If they get the problem correct they get a point, if they guess incorrectly the team who selected the problem has a chance to steal.
This is dueling, because the student has the choice of selecting a group to send a problem to battle.
Could you use this small review game in your classroom? What could you change to better adapt it to your students?