Try It, Try It, and You'll See...
After you've started incorporating games in your math class, your child may make comments like, "Boy, wouldn't it be great if we had a game that did x?" If you want to nourish this enthusiasm, you might reply, "Well, why don't we make one of our own?"
Designing a math game may seem daunting, but it's really not difficult. Most commercial games are variants on a few popular themes (see "Kinds of Games"), and once you're familiar with these categories it's easy to come up with your own take on them.
Just remember, kids have very powerful imaginations! Even if a game doesn't seem very original to you, or if the artwork doesn't seem great, your kids won't care. They'll be excited by making their own game - especially if they get to help - and will want to play it two or three times right away. Theme and game-play are the two key factors for how often they'll want to play the game down the road.
Theme
Young children generally go through phases where they're intensely "into" a particular topic. There is no better way to make math interesting than to design a game based on that topic.
As a first and second-grader, my son was constantly thinking about knights, space exploration and space combat, and also superheroes. Coincidentally, my "Game Ideas" section features knights, space exploration and space combat, and superheroes!
If your child likes ponies, try designing a pony game. If she loves plants and bugs, maybe she would enjoy a gardening game! The key is to build on your child's interests.
Game-Play
The nice thing about a game you design yourself is that you can adjust its difficulty. It's always a good idea build some flexibility into the game, so that it will grow with your child.
For example, a game designed for a first grader might contain only single-digit addition. After you have started to do multiple-digit addition and subtraction, you can add these into your game.
For some tips on how to do this, see the sections on dice and task cards. If you would like a concrete example, have a look at "Race to Altair."
Games as Family Projects
One way to make designing a game more fun is to get the whole family involved. After running an idea by my wife and son, they give me input. I then come up with the mechanics for the game and make the general outline for the board. But they're the ones who do all of the coloring and most of the illustrations.
We all get involved, and therefore it becomes "our" game. My son has also made up his own games, with just a few suggestions from me, and he loves to play these. Again, anything that builds on your child's enthusiasm is a plus!