http://msdn.microsoft.com/en-us/library/system.data.common.dbdatareader.getdatetime.aspx
ADO.NET data providers implement the DbDataReader, correct.
Edit: Alternatives
DateTime myDateTime = reader["my_date_time_column_name"] as DateTime? ?? DateTime.MinValue;
DateTime myDateTime = (DateTime)reader["my_date_time_column_name"];
DateTime? myDateTime = reader["my_date_time_column_name"] as DateTime?;