I just published my libguide for serious games. It has links off to resources that our library has for students but we also included a tab for mostly browser based educational games that a teacher with no funds could use. I did not include quizzes or games that did not seem like they would engage a student for long.
http://guides.library.unt.edu/seriousGaming
If you see something wrong or know of a game I should include, please tell me.
Thanks,
Diane Robson
UNT Media Library