http://chronicle.com/blogs/wiredcampus/at-indiana-u-a-class-on-game-design-has-students-playing-to-win/21981
Lee Sheldon, a professor at Indiana University, is indeed the epitome of creative teaching. Managing to incorporate video games into a mark book, Mr. Sheldon has accounted for the fact that we live in a social-networking, technology-immersed society. Instead of sticking to the traditional A, B, C grading system, Sheldon decided to use experience points (XP). Not only does this keep his students engaged in the class, but it motivates them to keep striving to achieve - and makes them feel more rewarded.
"Class time is spent completing quests (such as presentations of games or research), fighting monsters (taking tests or quizzes), and “crafting” (writing game-analysis papers and a video-game concept document). The 40-person class is divided into six “zones,” named after influential game designers, in which students complete group tasks." - The Chronicle of Higher Education
I'm not saying that you should necessarily forget the old grading system, but I have known a fair amount of teachers that use the gaming system to aid them in keeping their students motivated. They get their students to convert their grades to experience points (eg. a 95% could be 5xp, 85% is 4xp ...) and then write it down on a personalised chart. They progress through levels as they accumulate a certain amount of experience points, and each level is harder to obtain. Students strive to get to the highest level which usually has an attractive name such as 'The Mathematical Master.' Some teachers also modify this system to fit for each student by having them earn experience points by calculating the difference between their start of year grade average and the mark they've gotten on an assessment.
Gaming in education is a revolutionary concept for the modern high school classroom, and most definitely one that can be manipulated in a variety of ways by teachers.