Crusader Kings II v1.08 Patch

Also available via in-game autoupdater
Paradox Interactive has issued a new patch for Crusader Kings II, adding Nahua culture and Aztec religion, and optimized succession calculation, which could cause massive slowdowns in big dynasties with many landed members. Also, you can now forbid your council from leading armies and intrigue plots vs barons or their courtiers can now include their liege's courtiers and other vassals (thanks: The Patches Scrolls). A playable demo can be found here.