Now all modules are in core modules folder

modules/date/theme/date-vcalendar.tpl.php

@@ -0,0 +1,31 @@
+<?php
+/**
+ * @file
+ * Template for a VCALENDAR file.
+ */
+
+/**
+ * $calname
+ *   The name of the calendar.
+ * $events
+ *   @see date-vevent.tpl.php.
+ *   @see date-valarm.tpl.php.
+ *
+ * If you are editing this file, remember that all output lines generated by it
+ * must end with DOS-style \r\n line endings, and not Unix-style \n, in order to
+ * comply with the iCal spec: http://tools.ietf.org/html/rfc5545#section-3.1.
+ */
+if (empty($method)):
+  $method = 'PUBLISH';
+endif;
+  print "BEGIN:VCALENDAR\r\n";
+  print "VERSION:2.0\r\n";
+  print "METHOD:$method\r\n";
+if (!empty($calname)):
+  print "X-WR-CALNAME;VALUE=TEXT:$calname\r\n";
+endif;
+print "PRODID:-//Drupal iCal API//EN\r\n";
+foreach ($events as $event):
+  print theme('date_vevent', $event);
+endforeach;
+print "END:VCALENDAR\r\n";