HeroQuest got me into D&D. But The Hobbit got me into fantasy and sci-fi. We need a Hobbit movie!
Anyway, I proposed this idea a few years back in some thread or other. Basically, you have a series of related boardgames, and each boardgame has it's own unique dungeon or adventure. You take D&D minis and include them in the box, along with a prepackaged adventure aimed at 10-year-olds, and have characters included.
Taking a cue from the ridiculous 4e threads, I'd make it so that each adventure has 6 pre-made characters, who have their own card that lists all their powers and stats. Then there'd be various item cards, and each character could have two -- special swords, special spells, magic items, etc. If you beat an entire adventure, you'd be allowed to choose an extra card when you played the next adventure.
Really, it would have to compete with video games, but I think it could do that because you'd have minis (toys!), and the players would get to do things that video games might not normally allow. Each adventure would specifically start with a small bit of roleplaying, including a script for the game master to read. I imagine you'd have a ratio of about 1 roleplaying encounter for every 2 puzzles and 5 combats.
The key thing is presentability. If you can manage to get a great-looking boardgame for $30 or $40, and have a series of these things released every two months, hopefully kids would keep playing. It'd be like a collectable board game, where you try to get new items, monsters, spells, and maps.
I wish I could get a job at Hasbro doing this stuff. Maybe I should work on a proposal some time.