say-dates.php

<?php

class SayDate extends DateTime {
  public function say(){
    $now = new DateTime();
    $now->setTime(0, 0, 0);
    $interval = (int) $now->diff($this)->format('%r%a');
    
    if ($interval < 0){
      return $this->format('Y-m-d');
    }

    if ($interval == 0){
      return 'Today';
    }

    if ($interval == 1){
      return 'Tomorrow';
    }

    $weekInterval = $this->format('W') - $now->format('W');

    if ($weekInterval == 0){
      return 'This '.$this->format('l');
    }

    if ($weekInterval == 1){
      return 'Next '.$this->format('l');
    }

    return $this->format('Y-m-d');

  }
}

$dates = [
  '2013-07-26',
  '2013-07-27',
  '2013-07-28',
  '2013-07-30',
  '2013-08-09'
];

foreach($dates as $date){
  $date = new SayDate($date);
  echo $date->format('Y-m-d') .' -> '. $date->say() . PHP_EOL;
}


// Output:
//  2013-07-26 -> 2013-07-26
//  2013-07-27 -> Today
//  2013-07-28 -> Tomorrow
//  2013-07-30 -> Next Tuesday
//  2013-08-09 -> 2013-08-09