Millenaire is a very complete mod that adds randomly generated NPC villages to Minecraft. The villages are much more complex and varied than the default Minecraft NPC villages and provide more interesting gameplay.
Villages are constantly changing and will expand as you sell them raw materials through trading. You can buy regular items from villages, but unique village specific items including weapons and decorative blocks can also be purchased.
As you trade with a village your relationship with the citizens will improve and you can eventually become the leader. However, you may prefer to take over the village and destroy it!
Much more information including a beginners guide can be found on the official Millenaire website.
Download