******Another update: Another 75% off sale in late August.
Mount&Blade Warband and Napoleonic Wars are the ones to get in my opinion.
All Mount&Blade games/DLC are 75% off on Steam .
Napoleonic Wars (DLC) : http://store.steampowered.com/app/48705/
Mount&Blade collection: http://store.steampowered.com/sub/14259/
Community events in Napoleonic Wars such as linebattle events(http://forums.taleworlds.com/index.php/topic,236316.0.html )are quite a bit of fun I must say.
An example of one of the Napoleonic Wars community events:
As line infanry:
As cavalry( some bad audio in the start of it, sorry):
Steam group for public players to check out any events that allow (non-regimental players) :
Another example of some more Warband vanilla-like combat via Rome era mod: