9. "What Is Dead May Never Die" (Season 2, Episode 3)
By the gods, a description of this episode alone reads like a highlight reel for the whole season. In one hour [deep breath] we meet fan-fave Brienne of Tarth; watch Queen Margaery take it off and get real with her closeted husband King Renly; play the game with Tyrion as he outwits his rivals Varys, Littlefinger, and Grand Maester Pycelle; witness Theon Greyjoy's defining act of betrayal as he burns a warning to his friend Robb Stark and gets baptized into his father's rebellion; and listen as a grizzled Night's Watchman tells Arya that hatred can be sacred, right before he dies defending her. Power packed!