The Tapper Twins Go to War (With Each Other), by Geoff Rodkey (Little Brown, April 2015, younger middle grade) is tons of fun! 12 year olds New York city twins Claudia and Reese grate on each others nerves plenty, but it's not until Reese makes an unkind fart joke (implicating Claudia) in the school cafeteria that all out war is declared. And escalates, as Claudia realizes that humiliating Reese in kind isn't going to work (because 12 year old boys have different concepts of what constitutes social shaming--dead fish and Mohawk haircuts do not phase Reese).
So Claudia decides to strike Reese where it will hurt most--in a minecraft-like world where he has spent hours and hours building an empire, which Claudia destroys, getting herself into more serious trouble than she'd counted on, and making her feel rather awful too. Reese is also distressed by his own most cruel action in the war--uploading Claudia singing (badly) to her guitar about a new boy in their class....Even though the things they do to each other really are terribly unkind, their remorse and regret makes the story less uncomfortable to read than it might otherwise have been--like I said, I found it fun; even the squirmiest parts of Claudia's social humiliation were not as bad as they might have been.
It's told in the form of an oral history project, so we get to read direct observations from other classmates and the somewhat ditzy young woman who's the twin's after-school minder, as well as the original twitter conversations of the twin's parents (who care, but who are rather busier than usual with work during the time of the war). There are lots of pictures (including photographs) that further lightent the text. This format keeps the tension at bay and provides comic relief, and the resultant small-bits of story format make it one that will seem friendly and familiar to many young middle school kids of today.
Offer it to a sixth grade fan of Wimpy Kid!
disclaimer: review copy received from the publisher