This idea is as cute as it is potentially motivating. Over on ADHD Tutoring Tips you will find a great little idea for drill and practice exercises. I could see this working well for peer tutoring situations as well as homework sessions. You could pair students off into groups of two or three and have them practice as teams with each group working on a set of facts, words, or terms appropriate for their learning level or needs. This way, everyone is playing the same game, but learners who need more content that is more or less challenging can easily access it.