I ran games through my local "Community Education" system. It was called, "Introduction to Tabletop Wargames". I ran it for several years, consecutively. I always was asked to run additional classes as they always filled up, with students waiting. I was paid for running the classes, as well!
I wrote up rules which were easy to grasp for 10-12 year-old's, using plastic Army Men figures -- nearly every boy has these in his toy collection. I used d6-based rules, with rulers, and CRT's. No Tennis Balls, no clumps of dirt… They were well received, and students returned frequently, the following year, for another go at it.
I still play these rules myself, with friends. They play fast, with loads of tactical decisions to be made by each player. They're not terribly complicated, but they're not overly simplistic, either.
I ran my class for adults, also. It was quite fun to see adults crawling on the floor of the classroom, moving Army Men figures around… The youth classes were a much bigger success, but I still managed to attract adults, as well.
With the use of Army Men figures, the students tried to go home, and run their own games: students were issued Quick Reference Sheets for the class, but I took them back, at the end. The game was offered for sale, and a number of students purchased them, to play at home, with friends. Cheers!