Sorcerer [wiki], labeled "An intense role-playing game" is created by Ron Edwards, one of the founders of The Forge [wiki].
Before I even get into the mechanics of this game, let me first address what is probably the biggest concept of the game: demons.
In this game, you play a mortal human person who has the knowledge and the will to bring into this world Things That Are Not Meant To Be. The game is very clear that it is meant to be run that you are not summoning up nice faeries and things, what you are doing is pretty damned wicked. But then it leaves it up to you to figure out what it is exactly that you're summoning up. The game takes a pretty generic stance on it, calling them Demons, without really making statements on whether you're summoning up demon's from the Christian Hell or what. It does however encourage you to sit down with your players and figure out what kind of game you're running. The 'things' that the text calls demons can be: demons from the Judao-Christian Hell, the souls of the dead, spirits of animals and nature, internal demons (mental illness) given form by pure determination and fucked-up-ness, jinn and ifrit, terrible AI, or strange alien forces.
You create a character by splitting 10 points among Stamina, Will and Lore. Stamina is all things physical, Will is all things mental, and Lore is all things sorcerer. You get a Humanity attribute that is similar to Humanity from WoD. You get a Cover which is rather a career like Detective or College Professor or Career Criminal, that provides you with an income but also a quick and easy 'skill' type thing. If you're a Lawyer and want to go do some research on something, you're going to succeed based on your Cover, or perhaps roll some dice. Think of it as a really really broad skill, under which falls everything that might reasonably be a part of that job. You take a Price, which is a measure of how much you've already given up thanks to your dark art. Its any number of things, but is mechanically translated into a small penalty in some situations. You take a Telltale, which is just a 'tell', something that gives you away as a sorcerer to other sorcerers. Then you create a starting demon. Demon creation works similiar to creation of your character, there are stats like Stamina, Will, Lore, as well as Power, also abilities that the demon confers, the Desire of the demon, and the Need of the demon. Then you create a kicker for your character, and you're off and running. I'd wager that chargen would take a novice group between 15 and 30 minutes, maybe running longer if they're really chatty. Chargen here needs to be a group activity, otherwise you're going to have problems later on.
Tests remind me of a weird combination of Donjon and World of Darkness. Its comparative dice pools. If you have Detective Cover of 4, and want to use it to interrogate someone, you have a pool of 4 dice. Oh - the system states that you can use whatever size dice you want, as long as, of course, you're all using the same size dice. The size of dice used has a subtle effect on how the game works. Anyway, the system uses d10s as examples, and that seems a good size of dice to use. So you have your pool of 4 dice, which will be lowered or raised, the system is very strong about rewarding players for role playing things, and encourages dice bonuses for this type of stuff. You roll your 4 (or so) dice against my dice pool. My dice pool will either be decided by an opposing party's pool, like for the person being interrogated, there might be some kind of resistance roll, and I'll roll that number of dice. But if its against something that might not have a pool like that, there's difficulty that basically equates to... if its a task that's not notably difficult, or that advances the story, there is no resistance, it succeeds.... if its somewhat difficult though, the GM can roll a single dice in resistance, more difficult? half the players pool, so two.. even more difficult? equal to the players' pool, or even more than the players pool. Sorry - the mechanic you're looking for is high dice. You get 10, 8, 3, 3. I get um two dice and end up with 5, 1. You have two dice higher than my highest roll (10, 8 > 5). You succeed by two, which you can use on a subsequent related task. Or say you rolled 8, 6, 6, 4, I rolled 8, 2, 1. You get three successes- our 8's cancel and you do the math from there (6, 6, 4 > 2, 1).
Sorcerer is a single small hardback book, 141 pages, but its full of good stuff.
[Note: I wrote this up back on 8/1/06, and left it hidden, cause I didnt think I was finished with it.. it may still need some work, but it looks okay, so I'm putting it out there.]