+James Spahn and Barrel Rider Games need no introduction. James has made a name for himself in quality material. His White Star Sci-Fi setting for Swords & Wizardry White Box has not dropped below 5th place on RPGnow's hottest 100 listing since the day after its release nearly a year ago, and many of his over products dot the list on any giving day. I suspect, his newest product White Box Chivalry (aff) will be on the top 10 before I wake up in the morning; and for good reason.
White Box Chivalry is a 13 page box that adds knightly conduct, appointments, and life to the various fantasy worlds of Swords & Wizardry White Box. While mostly tables, White Box Chivalry is nicely detailed, and doesn't miss a beat in its explanation on the hows and the whys behind how a player-character could stumble into knighthood. All-in-all, its a good read and is easily implemented into any pre-existing game.
Unfortunately, it does have some flaws. The Accolade System, while awesome, is mildly confusing and I needed to read it three times before I got a handle on it. Also, while billed as being available for any race/class combination, it leans very heavily toward human/fighter (for obvious reasons) and is very hard for any other races or classes to achieve the honor. Still it is a minor gripe and one that leads to some interesting questions about different demi-human kingdoms (Dwarves instantly come to mind) and how the negative and positive racial modifiers would change based on location, peoples, and cultural values.
Like the majority of James work, White Box Chivalry is very gameable, and is seeded with the DIY mindset of the OSR. It works best as a framework to be altered, changed, and evolved/devolved to the liking of individual tables and groups.
Currently the small book is on RPGnow for a mild $1.99, and is worth the pennies for it.