I've used it as supplemental review for language classes and am now currently making a game where you learn a foreign language from scratch. Just make some sort of game teaching the concept (in my case vocabulary and grammar) in the game dialog. I like to color the words and grammar that are being taught per screen, for example "dog - kamooks" then the foreign word kamooks would be colored, or if you are learning past tense then "the dog ate" then "ate" would be colored. You can set up a signpost or something else in the game which will act like a book and explain the words/grammar either taught thus far, or in review.
In the current game I'm working on I have it set so that if you have 0 items of that type, it displays etymological text that looks like this when you first pick the item up:
aq - pick, pluck.
pi - thing (-age like package, luggage, postage)
k - noun.
aqpik (each part actually being a different color in-game) - "pickage" (direct translation with each corresponding part here being the same color as in the foreign word) - berry (the actual translation).
But if you have 1 or more item of that type, it only shows:
aqpik - berry
That way you aren't just "told something once and never again" despite that you only play once a week, which is a problem I have had in commercial games.
And with each scene, the language slowly gets harder and harder. As an example, the first screen may start with only listing plain nouns. You have to complete a quest before moving on to the second scene. The second scene may have "I want (noun that you previously learned)", and if you give the wrong item they say "I don't want (item you tried to give)".
Another way is to just make one mini game per unit that the kids are learning and give them access to it as a review.
If you are teaching kids programming, I would just give them a text file or printout with all the possible bitsy commands let them have at it...