a bad way to do mvc...

poorman_mvc.php

<?php

$location = isset($_GET['location'])? $_GET['location'] : 'home';

/// include the correct page if it is in our list, or open the home page
switch($location){
    case 'blog':
    case 'comments':
    case 'new_comment':
    case 'new_post':
    case 'archives':
    case 'old_posts':
        break;
    case 'home':
    case '': 
        $location = 'home';
        break;
    case '404':
    default:
        $location = '404';
        break;
}

include $location . '.php';
exit;
?>

<?php
// alternatively it could be this:

$pages = array(
    'blog',
    'comments',
    'new_comment',
    'new_post',
    'archives',
    'old_posts',
    'home',
    '404',
);

$location = isset($_GET['location'])? $_GET['location'] : 'home';

if(in_array($location, $pages)){
    include $page . '.php';
} else {
    include '404.php';
}
?>

<?php

/// a third (possibly less secure) way would be something like this:

$location = isset($_GET['location'])? $_GET['location'] : 'home';

//don't let them have . in the location url so they cannot go backwards up the filetree
if(strpos('.', $location) !== false)){
    $location = '404';
}

if(file_exists(MY_SITE_FOLDER.DIRECTORY_SEPARATOR.$location)){
    include MY_SITE_FOLDER.DIRECTORY_SEPARATOR.$location . '.php';
} else {
    include MY_SITE_FOLDER.DIRECTORY_SEPARATOR.'404.php';
}

?>

poorman_mvc_gone_wrong.php

<?php

/// taken from http://github.com/esokullu/grou.ps/blob/master/index.php
switch($function) {

        case 'join':

                if(!$access_isGroupMember) {

                        if(!isAuthenticated()) {

                                $pg->setLayout($pg->EqualColumns);

                                $signin = "<form method=\"POST\" action=\"{$service_host}?function=signin\">";

                                $temp_translation_string_1 = $treng->_("Email","groupjoin");
                                $temp_translation_string_2 = $treng->_("Password","groupjoin");
                                $temp_translation_string_3 = $treng->_("Keep me signed in unless I sign out","groupjoin");
                                $temp_translation_string_4 = $treng->_("Sign In","groupjoin");
                                $trengvar = array($service_host,$group_name);
                                $temp_translation_string_5 = $treng->_("Forgot your username and/or password? <a href=\"%TRENGVAR_1%%TRENGVAR_2%/recover\">Recover</a>!<br />Alternatively, you can sign in via your <a href=\"%TRENGVAR_1%%TRENGVAR_2%/openid\">OpenID</a>","authentication",$trengvar);
                                $temp_translation_string_6 = $treng->_("Sign Up","groupjoin");

                                $signin .= <<<EOS


                                <input type="hidden" name="join" value="1" />

                                <div style="height:30px;width:100%;padding:5px;">
                                <div style="float:left;width:100px;font-weight:bold;">{$temp_translation_string_1}</div>
                                <div style="float:left;width:auto;"><input type="text" name="username"></div>
                                </div>


                                <div style="height:30px;width:100%;padding:5px;">
                                <div style="float:left;width:100px;font-weight:bold;">{$temp_translation_string_2}</div>
                                <div style="float:left;width:auto;"><input type="password" name="password"></div>
                                </div>

                                <div style="height:30px;width:100%;padding:5px;">
                                <input type="checkbox" name="rememberme" value="1" checked /> {$temp_translation_string_3}
                                </div>

                                <div style="padding:5px;">
                                <input type="submit" value="{$temp_translation_string_4}" />
                                </div>


                                <div style="padding:5px; margin: 5px 0 0 0;">
                                {$temp_translation_string_5}
                                </div>


                                </form>


EOS;
//[ ... and it continues on for 100s of lines ...]

don't do this...

In the first example if $location == "home" then it will take you to a 404.

Fixed it!

Second file is bringing back nightmares of legacy projects