King Arthur's Pendragon
Pendragon is roleplaying game of arthurian era. Written by Greg Stafford (RuneQuest, HeroQuest, Call of Cthulhu), it is one of the most respected and influential RPGs around, thanks to its strong theme and narrative driving rules. Unlike most RPGs, Pendragon is very specific in its scope, and only type of character that can be created is knight. In the default setting, player knights serve earl Roderick of Salisbury, who, in the other, serves king Uther Pendragon. Uther rules all of the Logres, but he wants to extend his rule over whole England and be crowned as high-king. If story goes normally, Uther is murdered in 495, leaving Logres in anarchy until Arthur pulls Excalibur from the stone. The game "ends" in 566, when Arthur leaves for Avalon.
But isn't playing the knight limiting? Yes and no. The players are excepted to work in specific way, but knights have lot of adventuring. They serve their lords, fight against Saxons, take care about their holdings and family, take part in tournaments, and go to various quests. The game encourages getting married, as marriage gives glory, and dead characters are replaced by oldest son of the manor (if possible).
One of the greatest innovations of the game is the personality traits. Each character has 13 trait pairs that describe his personality. For example, one of the pair is Chaste / Lustful, describing how badly knight follows his cock. Traits are typically rated between 1-20, and when either trait gains value, other is lowered by same value.
When situation asks for it, the player has can roll against the specific trait. If roll success, the player must act like it is excepted by trait. If throw fails, second roll is made to see if the player needs to act based on the opposite trait. Otherwise the player can act freely. Of course, nothing demands player to roll, but if vengeful Sir Killalot constantly shows mercy for his opponents, GM will accordingly adjust the traits. The players are encouraged to aim toward high trait values, as these give glory and various other bonuses for the character. As a downside, character who has high rating in trait must always to roll against it or face reduction.
Trait system is fun, and it encourages playing in the role. In addition of traits, each character has passions. When doing something that is related to passion (i.e. defending their lord), the player can invoke passion roll. If it succeeds, the character gets bonus to the roll. If it fails, character gets depressed and can even go mad from the frustration. While this might sound ridiculous, arthurian era knights are very passionate, and it usually leads into misery.
Great Pendragon Campaign
The current of edition of Pendragon is consisted by two books*. First, rulebook called Pendragon covers the rules, and describes life in Logres in 485. It is nice and small book unlike its companion piece, Great Pendragon Campaign
. Great Pendragon Campaign
is massive tome of 450 pages, featuring over one hundred adventures between years 485-566. The idea is that the players go through whole arthurian era, from glory days to its miserable end, with family members replacing deceased ones. Even if played on weekly basis, it should take at least two years to finish the campaign. Running the campaign is very intimidating and cant' be recommended for beginners, as GM needs to keep track of dozens of people, alliances and vendettas. Fortunately, it is also very good sourcebook, with lots of neat ideas lootable for your own campaigns.
* Both are out of print, unfortunately. But DrivethruRPG sells both as a PDFs