<?php

function GetSummary($String) {
  $re1='.*?';       // Non-greedy match on filler
  $re2='(SUMMARY)'; // Word 1
  $re3='(:)';       // Any Single Character 1
  $re4='(.*?)';     // Non-greedy match on filler
  $re5='\n';    // Any Single Character 2

  if ($c=preg_match_all ("/".$re1.$re2.$re3.$re4.$re5."/is", $String, $matches))
  {
    $word1=$matches[1][0];
    $c1=$matches[2][0];
    $word2=$matches[3][0];
    return $word2;
  } else {
    return "NO MATCH";
  }
}

$data = <<<EOB
UID:5F12F7DA-10B0-4EE3-820D-B56F0B2FC153
DTSTAMP:20120408T041113Z
CLASS:PUBLIC
CREATED:20120408T041113Z
DESCRIPTION:Testfghfghfghfghfghfghfghfghfghfghfghfghfghfghfgh
DTSTART;TZID=America/New_York:20120410T000000
DTEND;TZID=America/New_York:20120419T010000
LAST-MODIFIED:20120408T041228Z
LOCATION:Philadelphia\, PA
SEQUENCE:1
SUMMARY:Test
TRANSP:OPAQUE
EOB;

echo GetSummary($data);