Students love getting to play the role of teacher! This makes it a reward they can work for. The reward can be getting to teach a game, a song, or a math lesson.
When students earn a certain amount of LiveSchool points, you can let them cash it in for this prize. Or you can make it a reward available to students who reach a certain threshold of points. It's up to you!
Simply allocate a short period of time for students to teach their peers about a topic of their choice.