Here’s my response:
I’m afraid I don’t have very good news for you. There are certain novels that are made into mainstream top-shelf games, but they’re typically big-name series. A grade-A game costs millions of dollars to make, so it’s like the film industry. Don’t call us; we’ll call you. Most game companies develop their games through internal talent.
There is, however, the equivalent of “small press” in the games industry. These companies tend to produce smaller, casual games that don’t cost nearly as much. They are sometimes open to submitted ideas. You can take a look at Big Fish Games, for example, and see what they’re doing. These are relatively low-budget productions, so don’t get your hopes up too high. Most of them have 8 hours of gameplay or less.
Alternatively, if you know anyone, or can cold-contact anyone, who is doing mobile apps, that’s another possible way to diversify into small casual games. You might try poking through the forums at a place like DevX or look around at GameDev.net for a hook-up with a programmer seeking a writer.
Good luck to my questioner and to anyone else who wants to turn their novel into a game!