Walter Jon Williams has also written a somewhat unconventional trio of books around a modern-day character named Dagmar Shaw who creates Alternate Reality Games as advertisements for blockbuster movies and games (Think of the ilovebees promo for Halo). But as it turns out, her skill set, combined with the intelligence and skills of her players, makes her kind of a mastermind. She attempts to user her powers for good while dealing with difficult real world situations.
The first book, THIS IS NOT A GAME, has some structural problems. It is written in three acts, and the first act is not terribly well integrated with the others, so that the book just seems to end in the middle and start over. Nonetheless, I would still recommend it just because I can't think of anything like it.
The second book, DEEP STATE, has Dagmar hired by spies to set up a "game" that backs a revolution against a totalitarian regime.
In the third book, THE FOURTH WALL, Dagmar goes Hollywood and runs a super-ARG in the manner of a Hollywood blockbuster. Interestingly, the narrator of this book isn't Dagmar herself, but rather the star of her game, giving you a very different perspective on Dagmar Shaw.
They're all interesting books, and I honestly can't think of anything like them. I say check them out.
Also, if you ever wanted to read his early Age of Sail historical adventure novels, they are now available as e-books. Good stuff.