HBO has a big problem on its hands. Its flagship show, the most-watched in the channel's history, is ending. So however Game of Thrones comes to its conclusion, we know that there will be one soon. And for obvious reasons, HBO would very much like to keep that money faucet going strong. But how?That was the question posed by The Hollywood Reporter to HBO programming president Casey Bloys."There are so many properties and areas to go to," Bloys said at the Westworld premiere in Hollywood. "For us, it's about finding the right take with the right writer."For their part, showrunners Benioff and Weiss have little interest in launching another massive fantasy series. They probably want to Scrooge McDuck for a while and not manage a transcontinental production involving every living British actor. But we cannot be without our Thrones or their attendant Games.Enter George R.R. Martin, who is nominally writing a book based on the popular TV series."I do have thousands of pages of fake history of everything that led up to Game of Thrones," Martin told THR at the Emmys. "So there's a wealth of material there and I'm still writing more."A popular theory is that there would be a prequel . Typically this would mean the Dunk & Egg stories, about King Aegon Targaryen's squirehood under Duncan the hedge knight. That would be a bit lighter fare, sort of the Better Call Saul to Thrones' Breaking Bad. Whatever happens, we're certain a spinoff is coming