I'm also hooked on Crusader Kings 2. I'm not even much of a history person, but I love maps, which is what drew me to it. Honestly, I think I've learned more history reading the Wikipedia articles of characters I've played in CK2 (and their kingdoms... and major events... and things vaguely related... oh how Wikipedia sucks me in...) than I ever did in school.
It took me quite a few games to get the hang of it. Starting as a count or duke helped curb the things I had to manage as I was getting the hang of it, but now that I know what's going on being a king is a lot of fun. Taking over places, assassinating people, and generally messing up history is awesome! I got the Old Gods DLC not too long ago just because I like anything Norse, and I've been taking over all of Scandinavia!