Civilization 5 yet, have heard good things about the Gods and Kings expansion, and have a steady Internet connection to play games on, then streaming service OnLive has a deal for you. It's offering the Civ 5 core game PlayPass for free when you buy Gods and Kings, essentially giving you the entire critically acclaimed title and its add-on for $29.99.
What you're buying here is the chance to play them on OnLive, however, which gives you the benefit of running the game as if you're on a high-end PC (even if you're on a Mac or a low-end PC), as long as you have an Internet connection with the bandwidth to stream it. As long as you've got the pipes for streaming HD video, this is the way to jump on the Civ 5 wagon, as the same deal on Steam will currently run you $60. OnLive says the door's closing on this one at the end of this week.