WTF

-> .htaccess
AddDefaultCharset UTF-8
RewriteEngine ON

ErrorDocument 401 /error/401
ErrorDocument 403 /error/403
ErrorDocument 404 /error/404
ErrorDocument 500 /error/500

RewriteRule ^(.*)$ index.php?url=$1 [QSA]
-> index.php
<?php

if (session_status() == PHP_SESSION_NONE) {
    session_start();
}

spl_autoload_register(
    function($className)
    {
        $classPathCore = 'modules/core/'.lcfirst($className).'.inc.php';

        if(file_exists($classPathCore)) {
            require($classPathCore);
        } else {
            $classPathParts = explode('_', $className);
            $classPath = 'modules/'.lcfirst($classPathParts[0]).'/'.
            lcfirst($classPathParts[1]).'.inc.php';

            if(file_exists($classPath)) {
                require($classPath);
            } else {
                header("HTTP/1.0 404 Not Found");
            }
        }
    }
);

Core::loadPage();

?>
-> modules/core/core.inc.php
<?php

class Core
{
    public static function loadPage()
    {
        $moduleName;
        $moduleAction;
        $moduleParams;

        $url = $_GET['url'];
        $urlParts = explode('/', $url);

        if(!empty($urlParts)) {
            switch(count($urlParts)) {
                case 1:
                    $moduleName = array_shift($urlParts);
                    $moduleAction = "default";
                    $moduleParams = null;
                    break;
                case 2:
                    $moduleName = array_shift($urlParts);
                    $moduleAction = array_shift($urlParts);
                    $moduleParams = null;
                    break;
                default:
                    $moduleName = array_shift($urlParts);
                    $moduleAction = array_shift($urlParts);
                    $moduleParams = $urlParts;
                    break;
            }
        } else {
            $moduleName = "Main";
            $moduleAction = "default";
            $moduleParams = null;
        }

        $controllerClass = $moduleName.'_Controller';
        $controllerAction = $moduleAction.'Action';

        if(class_exists($controllerClass)) {
            $controller = new $controllerClass();

            if(method_exists($controller, $controllerAction)) {
                $controller->$controllerAction($moduleParams);
            } else {
                header("HTTP/1.0 404 Not Found");
            }
        } else {
            header("HTTP/1.0 404 Not Found");
        }
    }
}

?>