Angular:

http://angularjs.org/

by mrajcok

HTML

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.0.7/angular.min.js"></script>
<div ng-controller="MyCtrl">
    <div ng-click="clicked()" get-siblings>One</div>
    <div ng-click="clicked()" get-siblings>Two</div>
    <div ng-click="clicked()" get-siblings>Three</div>
</div>

CSS

.clicked {
    color: red
}

JavaScript

var app = angular.module('myApp', []);

app.directive('getSiblings', function () {
    return {
        scope: true,
        link: function (scope, element, attrs) {
            scope.clicked = function () {
                element.siblings('div').removeClass('clicked');
                element.addClass('clicked');
            }
        }
    };
});

function MyCtrl($scope) {}