Video Games in the Classroom?

I really enjoyed reading the Innovative Educator's blog about "Game-Based Learning Site for Innovative Math Educators". These games seem great! In large classroom, games like these may serve as a solid solution to busy work using a pencil and worksheet. The games will monitor correct/ incorrect answers while students play. Teachers who have mixed level classes, could work and teach a lesson with one group of students, while other children hone their skills while playing an interactive scholastic game. I have two 7/8th grade Algebra classes this year, but they are both full of mixed levels. Each class has contains students who have a full year of algebra behind them, some students have only taken pre-algebra, and some students need advanced algebra/ geometry instruction. I could certainly use a website like this in my class as an instructional tool.