Blood of the First Men (Agenda): "You may run any number of The North agendas. You need 2 additional power to win the game. Reduce the cost of the first Wildling character you play from your hand each round by 2."
+
Varamyr Sixskins (Character, Neutral, 2-gold, 2-str M/P): "Any Phase: Put 1 Creature character into play from your hand to return Varamyr Sixskins to your hand. At the end of the phase, if that Creature is still in play, discard it from play (cannot be saved)."
+
Balerion the Black (Character, Creature, Dragon, 10-gold, 10-str, M/P) Response: After you play Balerion the Black from your hand, kneel all non-Dragon characters and locations.
Yes, Balerion gets discarded at the end of the phase, but all it cost you was a card from your hand.
Imagine running this out of Greyjoy, and playing "Rise of the Kraken," winning initiative, and then executing this combo as your first action in the challenges phase. The single power challenge that Balerion could do would net you 5 power (2 for claim, 2 for unnaposed, 1 for renown), which could easily be a game closer.
You don't even need the agenda, really, but with it, and an ample supply of dragons in your deck, you could do something like this every turn, for free. And it works with any house; Varamyr is neutral, and none of the dragons are "House Targaryen Only." You could include a couple copies of "Dance with Dragons" (core set) to get the dragons in your hand when you needed them.
What do you think?