I use the contentgenerator.net games for review purposes in my classroom - the kids like them. Hot Potatoes is also really great for reviewing - especially since you can add feedback on the answers.

If you can open flash files (.swf) on your computer, here is the post I left on the contentgenerator.net forums when someone asked for review games for English - I listed quite a few games (but I teach 8th grade) if you want to see some examples.

http://www.contentgenerator.co.uk/forum/index.php?s=&showtopic=601&view=findpost&p=5247 

The Hoop Shoot Game and Grade or No Grade are made with game engines you have to purchase. The others are all free. The format is very simple to use. Just type in the questions and the answers. Nothing to it. If you can't open the .swf files, just replace the .swf extention in the URL with .html - the game will just be a little smaller on the screen, that's all.

Go here: http://www.contentgenerator.net/ if you want to download the game engines.

Hot Potatoes is also free:  http://hotpot.uvic.ca/

Here are some examples (again, 8th Grade English)

http://eclassroom.110mb.com/1st%209%20weeks%20web/1st_9_Weeks_Exam.htm

Hope this helps.