Since it looks like The War of Five Kings is the setting that's getting the most votes is there any details I should know besides that Robert's brothers, Robb Stark, Greyjoy, Joffrey are the kings trying to kill each other?
Well, lots.
But, that's the basic part of it, from the view of a commoner.
You should know the general setup of allegiances at the start of AGOT, from this handy map!
The North (The Stark Wolf/Claimant to the Iron Throne, the Usurper Robb Stark)
The Vale (The Aeryn Eagle/Starts Neutral)
The Iron Isles (The Greyjoy Kraken/Claimant to the Iron Throne-maybe-the Usurper Balon Greyjoy.)
The Riverlands (The Tully Fish/Supports Robb Stark, under attack by the Lannisters)
The Rock (The Lannister Lion/Currently Holds the Iron Throne via Jofferey Baratheon, claimed as the previous King-Roberts-Trueborne heir.)
The Reach (The Tyrell Flower/Supports Renly Baratheon, Roberts younger brother.)
The Stormlands (The Baratheon Stag/Claimant to the Iron Throne, the Usurper Renly Baratheon)
The Dornish Marches (The Dornish Sun and Spear/Starts Neutral)
The Usurper Stannis Baratheon-Robert's second brother-has also claimed the Throne (He's actually the rightful ruler by law) but has the least power, initially, of any house.
See, it's called the Seven Kingdoms-but Dorne has never been conquered, despite being the 8th-though it has bent the knee to Westeros, peacefully.
Also is there magic in this?
Well...yeah, but it's not anything you'd ever want to use. Or do you?
I can't explain it, but...really, magic is extinct by the time of the War of Five Kings, and there are no wizards slinging fireballs, or casting "summon food"...though, the magic may be coming back. And, that's not a good thing...read the books if you want more.
See-what hints of magic there is, is fairly terrible. For example, the way to get a magic sword? Quench it in the blood of someone who loves and trusts you. Want to bring a Dragon to life from stone? Better burn someone of Royal Blood-only a King will do! Need a Shadow Demon to assassinate your enemies? ...we'll, I'll let you all figure that out by yourself. None of this is available to you, or any of you, at the start of the game.
The best quote to summon how magic works in AGOT-
"Sorcery is a sword without a hilt. There is no safe way to grasp it"
Why would we kill each others? We're all loving brothers and sisters!
No really!
This is meant to be a
cooperative game. You must work together to survive.
I will not offer you any incentive to backstab each other, though I cannot forbid it exactly-I'll just make sure they'll be plenty of enemies, willing to do the same for you.