This post is as much about fleshing out my comprehension of the material as it is about sharing it with others.
Vincent Baker, like four years ago, came up with a generic version of the core mechanic for his 2002 design, Otherkind, which was a game about fairy-like creatures trying to flee the world of Man with as much Numina (mystic essence-stuff) on hand as possible. Their opposition: Men, with their Iron.
In the original design, (thanks, RPG.net!) you roll four dice whenever you attempt something. Then, you take the dice results and apply them to four categories:
Narration - does the GM or the player get to narrate?
Motion - did the character accomplish what he set out to do?
Life - did the character harm anyone in the process?
Safety - did the character get hurt in the process?
Only Life needs further explanation - it's anathema to the Otherkind to destroy life; Numina is the very essence, sort of the divine byproduct, of life, so of course causing death is super-bad for them, and makes them more like Iron (which is really bad!). I've been unable to find the original full entry on lumpley.org that explains all the rules, but this is what I can recall.
Anyway, here's the distilled essence of the game, usable as the core of any setting or whatever:
roll 3d6. After you've rolled them, assign one each to the three things.
Assign one of the dice to the accomplishment at stake:
1-2: the character does not accomplish it. The character punches him but doesn't get past him. Update the circumstances and roll another conflict, or go forward with the accomplishment totally unachieved.
3-4: the character makes progress toward the accomplishment, but doesn't achieve it outright. Update the circumstances and roll another conflict, or go forward with the accomplishment partly achieved.
5-6: the character accomplishes it!
Assign the two remaining dice to the two dangers:
1-3: the danger comes true.
4-6: the danger doesn't come true.
If the 1-2/3-4/5-6 scale works for the dangers too, feel free to use it.
So say I roll 1 3 4. How do I assign them? It depends on my priorities, of course. Maybe what matters most to me is Millicent's regard: I assign 4 to that danger, so it doesn't come true. Maybe what matters next is getting past the guy, who cares about a black eye: I assign 3 to getting past the guy, we'll roll again, but pow! he gave me a real shiner.
Say instead I roll 4 6 6. I do the butt dance of victory!
The system here isn't necessarily complete - as it stands, there is, obviously, no room for any traits specific to the character to directly affect the dice rolls. Traits might be relevant as hell for assisting assignment of dice, but they don't give pluses or minuses or allow rerolls or anything. Yet. Notice that you always succeed in the task - in true Firefly fashion, failure comes not from a lack of ability, but from complications that arise as a result of plowing on ahead.
This doesn't mean that people never fail at anything, ever. It means that the thing you've put your mind to is beyond the icy grip of failure; where it gets complicated is that what you were trying to do through the action might screw up (as simple as performing an amazing crack-shot ... on the wrong guy).
So. Easy way to make things more complicated: if you're attempting an action that your character is good at, that is really important to your character, etc., then you could get bonuses on the dice results. You'll notice that higher is always better (thanks, Vincent!), so this is an easy way to "break into" the mechanic and start messing around. You could instead add more dice and more complications - more things can go wrong, but you also have a bigger pool of dice to choose from to put things where you like.
Three things: 1) since you automatically succeed at the task itself, it's up to the Social Contract to enforce what sort of tasks you can attempt in the first place. 2) Any player should be allowed to take on more dice (and for each one, a complication/thing that could go wrong), gaining the benefits mentioned above. 3) Characters get some number of points to put into traits they possess; whenever you use one of your traits to perform a task, you can use all the points attached to it to change die results, 1 point per pip on the die. This represents the greater control in the overall situation that comes with mastery of a skill.
Lastly, I think I've changed my mind about the "lack of setting" presented by this system. You go to people, explain this system, and then ask them "so, what do you feel like playing?" If they're gamers, they'll come up with something. If anything, this could actually increase your odds of finding something folks like, or scratching an itch somebody has had lately - you guys just saw The Mummy again and want to do that, but nothing on your gaming shelf has that genre. Good stuff.