In this day and age of entertainment, little and less can likely be found which has a similar level of popularity as Game Of Thrones. If anything were to come close, however, it might be Pokemon, and by extension, Pokemon GO. Although not available everywhere around the globe just yet, Pokemon GO just recently launched in the U.S. and a few other regions officially and is slowly continuing to roll out to a handful of other countries, and already it's gained a massive following. It might be the fact that the game is still fresh, but the level of energy and excitement surrounding the game has reached untold levels, allowing players to walk around and catch Pokemon and gain control of gyms. What could possibly be more popular? Perhaps a Game of Thrones version of the game.
One of Pokemon GO's developers states that he has a vision for creating a game like Pokemon GO that carries a Game of Thrones theme, where players would be able to travel the lands of Westeros and Essos as they walk around in the real world. Just like players in Pokemon GO have the option to join one of three teams, including Team Valor (Red), Team Mystic (Blue), and Team Instinct (Yellow), the idea is that players of the game would have the opportunity to join a particular house from the Game of Thrones universe.
Naturally, a game of this nature would potentially spark an interest in those who love Game of Thrones, but for now, a dream is what this will have to stay as Niantic has not voiced any plans to make such a game and turn it into a reality. Archit Bhargava, the developer who mentioned that it would be a fantasy of his to create this sort of game, brought it up in an interview with Gamespot when speaking about Pokemon GO. Among dreaming of traveling the lands of Westeros under the banner of House Stark (or whatever house he might choose), Bhargava also discussed other plans that the team at Niantic has for Pokemon GO's future, and that the team is still exploring how to implement a multiplayer aspect beyond gaining and holding control of gyms, as well as stating that players will help to shape the game.