const String dateString = "2012-11-20T00:00:00Z";
var offsetDate = DateTimeOffset.Parse(dateString);
var offsetDate2 = DateTime.Parse(dateString);
Output is
offsetDate {20-11-2012 0:00:00 +00:00} System.DateTimeOffset
offsetDate2 {20-11-2012 1:00:00} System.DateTime