Don't know if you guys noticed but this week it's Sid Meier Bundle on Humble Bundle and they just added even more to it:
Aye, we've added more content to the Humble Sid Meier Bundle! Sid Meier's Pirates!, Sid Meier's Civilization V: Scrambled Nations Map Pack and Sid Meier's Civilization V: Scrambled Continents Map Pack are now available when you pay more than the average booty.
So now it's Civ 3, Civ 4, Civ 5 + Gods + Brave New World and a few map packs, Pirates, Ace Patrol and Pacific Skies + Railroads.
Not too shabby if you missed Civ 5 when it came out.