I'm reading this book right now. It's smurfing awesome (but somewhat depressing at the same time). For those of you that don't know the story it goes like this:
In the near-future Japan, everything is falling apart. Unemployment is at an all time high. Students are boycotting school, even physically abusing teachers. As a desperate attempt to end the disrespect between kids and "grown-ups" the adults passed the "Battle Royale Act" (or, simply, "Program" in the novel). This program takes 42 unsuspecting kids and tells them that they're going on a "school trip". They are gassed, put on a deserted island, and put on metal collars. They are then explained to that they have to kill each other, and the last one standing gets to go home, but only if everyone is else is dead (in the movie they are given 3 days, and if more than one person is still alive all the neck collars go off; in the book there is no time limit, but if 1 person does not die in 24 hours all the neck collars go off). The collars on their necks monitor their pulse, tell their location, and also has a bomb inside of it (if the student tries to rip off the collar, it will explode, or if they break a rule or wander into a danger zone). They monitor their location because there are danger zones on the island that they must not go into or else their neck collars will explode. Every 3 hours the leader of the program (Sakamochi) gives them updates via speakers throughout the island. With these updates he tells them who died and where and when zones will become danger zones. After that they must leave the school (which is where they were explained the rules and everything is being monitored. It is also a danger zone from the beginning, so the students can't get near it to attack or something like that) with a pack that has several things: water, food, a map of the island, a compass, a flashlight, and a weapon. Each weapon is unique, not being just guns and knives. This means that the weapons that are given vary from Shotguns to butterfly knives to even potlids and binoculars. The question is: would you kill your best friend to live? Many go crazy and start killing, some commit suicide, and some vow not to kill. (Oh yeah, also another interesting thing, this "Program" happens 50 times a year, and the kids know that it might happen, but just ignore it out of hopes that they won't be unlucky to get picked; they also don't know the conditions of the game)
A very good book, but its plot is a bit questionable. Would Japan go that far just to curb its misbehaving students? This is may be the only thing that might stop you from reading the book, because if you don't believe the plot then you'll never really get into the book. It might also be confusing sometimes too, because there are 42 students and sometimes it's hard to keep track of who died and who's still alive. Also, it's a bit gory, so I recommend that the squeamish would stay away... Other than that, it is an excellent novel (and movie; I also recommend that too) that should be read by all of love action and suspense.
P.S. It's also has an awesome (and very graphic) manga... check that out if you don't want to read a 700-page book :P