Motivating Students to do Homework

I tried using the scoring system from WIN TV's "Hotseat" as a way of providing feedback to students on their homework performance. The class I tried it with was a low performing year 10 maths class but I expect it will work with a wide variety of classes in secondary schools.
What I did was write a vertical list of scores on the right hand side of the white board to mimic the layout in the TV show. (ie from bottom to top $100, $200, $300, $500, $1000, $1500, $2500, $4000, $6000, $10000, $20000, $50000, $100000, $250000 & $1000000.) I marked the level they were at based on whether they answered the homework questions and crossed out the top levels when a wrong answer was given. They got to the $1500 level showing they weren't performing well. I did create enthusiasm. I'll try it again and see if it translates to the class as a group being motivated to do better at homework.