The best educational games are the ones that don't seem to be educational. They don't dress up rote learning with graphics and sound effects. They require a bit of critical thinking as well.
I'm addicted to Zynga's social games (like everyone else with an iPhone) such as Words With Friends and Scramble With Friends. They're fun because you're playing against a real person, but they're also educational. Both games force you to delve deep into your vocabulary and do so rather quickly.
So while playing Scramble, I imagined replacing the letters with numbers and asking players to create different combinations that would add up to a certain goal. With just a few tweaks to Scramble's interface and mechanics, you could easily make a game I'll call Numbers With Friends that would be just as fun, addictive and educational as its predecessor.
Take a look at the mock-up above. Each round, you'd be given a goal number and run your fingers across the numbers to create the right sum. The more combinations you can find and the more numbers you use add to your score. For example, could press just the -6 alone for 1 point, or press -5 + 0 + -8 + 0 + 6 + 1 + 1 for 7 points.
I don't claim this to be a completely original or revolutionary idea, but I'm taking a common number sense activity and putting it in a package that almost anyone would love to play. If I knew how to program (and how to not get sued) I would make this myself, but I've always been a fan of not reinventing the wheel if you don't have to.
Mashable! reports that Zynga's business is a bit down at the moment, so this is the perfect time for a modest offer: I'll gladly take a job or a big fat check for my surefire idea. I'll be awaiting your response.