If you're not a fan of Lost, or if you have not seen the episode that aired last night, 4/6 ('Happily Ever After'), please avoid this discussion. You either won't get it, or you'll get too much of it.
If you were waiting for the poo to hit the proverbial fan, Desmond Hume delivered the goods, so to speak. I've watched Lost from the beginning, and I've seen every episode probably a half-dozen times, and no single episode had me on the edge of my seat for 60 minutes quite like last night's episode. Not only was it huge in terms of bringing the plot to a head and pointing us in a definitive direction over the last seven hours of the series, but the character reveals, cameos and overall story of the episode were brilliantly executed.
... whoa. This episode was epic.