Crusader Kings 2 is a bit of a gem. The strategy game is one of the most mechanically interesting out there, focusing on building family names and managing your dynasty. It's the best Game of Thrones game and it isn't even Game of Thrones themed (unless you install the excellent Westeros mod.)
You don't have to take my word for it though. You can go trial the game to your hearts content over the next week. The title is free to try on Steam until February 23rd. If you enjoy your time, the game is also 75% off, so it's going for pretty cheap.
I wholeheartedly recommend giving it a go, but you might want to watch a few tutorial videos first. It can be tricky to dive into cold. If you stick with it though, the game will bite you. Just, you know, don't go playing it for 10,500 hours.