Mount & Blade: With Fire and Sword Siege trailer

Mount & Blade (and the later Warband) is one of the games I always have to have installed. Usually for the mods, which are far better than the vanilla game in every possible way. Typically.

With Fire and Sword adds (officially) guns. Among other things (which you can read about if you like), including a new map and an entirely different time period, fully customizable armies, new multiplayer action (command AI troops in addition to general deathmatch), better towns and economy modeling. Most places have it for $15 or thereabouts, though initial reviews aren't so great this time around.