I use computer games in my class on a regular basis. I have three computers available for the students to use during both the math and reading period. During a typical math lesson period I rotate the students through the computers using a math practice site xtramath.com for them to practice their math facts. Since my class has 25 students in it we do not always get through the entire class each day. I try to have the students on their fact practice at least 2-3 times each week during the lesson time. On Thursdays the class spends the first part of the period in our school computer lab where they complete their fact practice, and then have games from three different sites available to them to practice other math skills. The sites I set up for their fun practice are math-play.com, ixl.com, and sheppardsoftware.com. Each of the sites provides a large variety of games and I can give the students a specific game to play that aligns with the weeks lessons or concepts covered in class. The other really nice thing about all of the sites available are that they can be used by multiple grade levels from K-8. This allows the teacher to tailor lesson extensions or interventions to the student. My students really enjoy accessing all of the sites and in for any reason we cannot use the computers they are really bummed. If I have any new games that I want them to try I will do a whole class introduction using the Promethean board. This usually gets them so jazzed to play that we plan for the next day.
I talked regularly with my teaching partner about the sites that both he and I access for our students. I also talk with the teachers both below and above my grade level to get their input on great math sites for students to use.
Overall I think computer games are a great tool for teachers to use in their classroom to help students who need or would benefit from either intervention or extension activities. They allow for a wider range of differentiation activities and possibilities for all students.