http://www.taleworlds.com/
I had heard of this before, but only tried it out yesterday. It's a standalone medieval rpg that is still in development by a small Turkish dev team, but you can download and play for free up to level 6 (you can then buy a license to continue playing, and support development).
It's not 'hte shiny', it's low budget and looks it, but the combat is fun.
I've only really just started and have just been playing 2v2 and 3v3 arena battles in the starter town, but that in itself is fun. It's twitchy, where you can be on foot or on horseback using bow, swords or polearms (Jousting!!).
Just something else to waste time on while you should be doing something else.