Mine

<?php
//For some reason this will crash Apache.

// A function that records the time when it is called
function profile($dump = FALSE) {
  static $profile;
  // Return the times stored in profile, then erase it
  if ($dump) {
    $temp = $profile;
    unset($profile);
    return $temp;
  }
  $profile[] = microtime();
}

// Set up a tick handler
register_tick_function("profile");

// Initialize the function before the declare block
profile();

// Run a block of code, throw a tick every 2nd statement
declare(ticks=2) {
  for ($x = 1; $x < 50; ++$x) {
    echo similar_text(md5($x), md5($x*$x)), "<br />;";
  }
}

// Display the data stored in the profiler
print_r(profile(TRUE));

?>