First is a web site called HA Games. This web site, which requires a login, has games focused on Algebra, Physics and the Periodic Table.
You can also check out games based on Nobel Prize winning research. These games cover the topics of physics, chemistry, physiology, medicine, literature, peace and economics.
Here are some simple games to teach about energy conservation over at the Energy Hogs web site. These games might be too simplistic for older students. If that is the case, have them examine the games and see what improvement or changes they would make.
You can go to the EdHeads site and check out games focused on teaching about simple machines and crash scene forensics. The games are accompanied by teacher focused materials so you can incorporate them into the classroom (also a few medical focused games and one discussing the weather.)
Teaching basic math is a site called Academic Skill Builders. This site covers a number of basic skills such as math, verbs, addition, etc.
If you teach biology, you might be interested in a site called Frog Guts where you can virtually dissect a frog.
Here is a first-person shooter game for teaching about algebra. The demo focused on graphing. Go to Tabula Digita's web site and check out their game Dimenxian. I've written about this game before in my blog posting Learning Algebra in a Game.
To teach basic multiplication skills check out Timez Attack which I have written about before in my post Learning Multiplication Tables in a Game. Here is the web site where you can download the free demo.
Finally, you might want to check out Immune Attack to learn about the human immune system. You are shrunk to the size of a blood cell and propelled through a body to learn about how our immune system works.
Learn more about Games for Learning at the web site Gadgets, Games and Gizmos for Learning which discusses my book by the same name.
Check out Going to the MUVEES to See River City to learn about a game which involves many students working together to solve a science problem.
Here are some of the underlying reasons why we want students to "Play Games."
Catalog of Recommended Books, Games and Gadgets
Recommended Games and Gadgets