Quia is a pay service, but one well worth the $49 a year. The site allows you to create several different type of online games including "Who Wants to be a Millionaire", "Jeapordy", and "Battleship" like games. Of course they use different names for the games so they don't get sued. The variety of games allows you to focus on concepts, vocabulary, or standardized test review. You can also create online quizzes that allow you to track student progress.
I have used this site for about 8 years and the kids never get tired of playing them. I've used them for academic competition preparation as well as for test review. You might also consider presenting this to your district to pay the $49 a year with the promise of using the program to create review games for the district. Even after your account expires, the games stay live and can be used forever (you just can't edit them any more).
Here's the ling to the site: QUIA
And here's a sample game: GAME
Most districts now provide an online platform for teachers to house course materials and complete activities. One of the best and most used among universities for online courses (at least in my area) is Blackboard. Blackboard also happens to be one of the most expensive, and has often been a casualty of budget cuts of late.
Thankfully Blackboard also offers CourseSites which is a free version very similar to Blackboard that individual teachers can use. So if your district doesn't offer an online platform or the district has cut funding for it, CourseSites can come to the rescue.
CourseSites is very similar to Blackboard, though the look of it is a little different. Since it is not a district wide platform you will have to invite and administer the students yourself which does add a certain level of responsibility. You still have the function of creating tests, surveys, discussion boards, blogs, etc. CourseSites also allows you to integrate published texts and their ancillaries at a certain cost.