<?php
    $date 
= new DateTime'2010-03-08 15:48:21' );

    
$date->setTime150);
    
$date->setDate20080722 );
    
$date->setIsoDate200845);
    
$date->setTimestamp1200128314 );
?>

Result:
2010-03-08T15:48:21+0000
2010-03-08T15:00:07+0000
2008-07-22T15:00:07+0100
2008-11-04T15:00:07+0000
2008-11-15T08:58:34+0000