(this is an excerpt from an e-mail I sent to a friend)
I've started thinking whether one couldn't make a textbook of games. Rather than reading two pages in a text and answering set questions for each lesson (which is what happens in most classrooms I've seen), students would play a short game then reflect on the experience, or a component of a game designed for 4-5 lessons. It would still appeal to teachers who lean on textbooks as the entirety of their course (truly inexcusable, but it's a market). It would appeal to schools worried about kids getting disengaged and dropping out. And if it were well-designed it could have all of the learning merit of a textbook, combined with the merits of games.
In my experience, there are a few restrictions on designing games for educational settings, which actually make them easier to design as they set convenient boundaries on the project. Note that most of these apply to games to be played in a single period, I'd have nothing against a game designed to take 5 periods.
1. The rules have to be simple enough to explain in ten minutes or less. If your rules fill more than an A4 sheet of paper, they're too complicated.
2. The game needs to be playable within a confined time space. Either design it so that it ends when certain objectives are achieved, which one can expect to be achieved reasonably soon (sometimes with teacher coaching), or it can be cut off partway through with no real consequences (i.e. a trading game where students are trying to make a profit, so you cut it off after X minutes and ask who's the richest).
3. The game needs to achieve certain clearly defined learning goals. A good educational game will introduce two or three concepts (supply and demand, the floating value of money) and open up some questions for discussion.
4. The game should fit into a program of teaching. What do students need to understand to play? What will they learn and be able to use after they play?
The fun thing about being a teacher is that you can make a game designed for twenty players and be guaranteed enough people to play. You can watch, or design a role for yourself (banker, journalist, whatever). Keep in mind that games vary. Educational games tend to sit on a spectrum between Simulation and Role-play. A pure simulation, like a card game or board game, creates rules and structures for players to work in. They have clearly defined goals and chase them. Then they can reflect on how the rules and constraints of the game reflect the real world, or not. Role-plays are much more about discovering the motivations of actors in the real world, and examining how they interact. A lot of games can incorporate elements of both.