Although I’m not playing it right now, Greg Stafford’s King Arthur Pendragon is on of my favorite RPGs ever.
Over at Refereeing and Reflection, a post just went up giving a terrific overview of the game by someone who played through a solid chunk of The Great Pendragon Campaign.
If you’re not familiar with the game, but curious about it, you might want give the overview a shot. It describes not just the mechanics, but the overview of session and campaign play.
Tales to Astound! 
My favourite RPG. I have been GMing it since 1987. I currently run a few campaigns on makofan.lefora.com for anybody interested in its flavour