$xml =
'<derp>
    <Choice ID="1000">
        <Select NAME="BOB" />
        Monday
    </Choice>
    <Choice ID="1001">
        <Select NAME="Mary" />
        Tuesday
    </Choice>
</derp>';
$dom = new DOMDocument('1.0', 'UTF-8');
$dom->loadXML($xml);
foreach($dom->getElementsByTagName('Choice') as $choice)
{
    $arr[] = $choice->textContent;
}
print_r($arr);