http://digitaltoolsforteachers.blogspot.com/ ) recently about interesting instructional gaming websites. Here's one called SHIDONNI...The following link contains a PREZI presentation about Shidonni...It may be geared toward younger students, but I still see potential--especially as a learning station in your class where students might work colaboratively together to create a world: (thinking about the 8th grade who studies ocean zones, 6th grade who studies planetetary systems, etc)
Here's a site called Game Classroom that has games organized by grade level and subject area, it only goes through 6th grade but for those lower skilled students, some games may be appropriate for 7th and 8th graders too!
Here are just all the games listed by grade level:
Then, if you want to search through lesson plans, etc. that go along with the games go here to the main website:
If there is a game on the topic, it will be at the bottom of the page that has the lesson on the particular topic. Each lesson also has on-line resources.
Then, there are sites that help train your brain, Here's one called Fit Brain.
Another one in this genra is lumosity and it has focus games, problem solving skills, match games, etc.:
For both of these web-sites I signed up for a generic account that you can use: tjmswsnc, pw: (hint, 3500)
Finally, here are some more Math Games that Stephanie Hendy collected in her blog: