timestamp can both be null and have a default

gistfile1.txt

mysql> create table temp3 ( id int, bleh  int default null default 1, tstamp timestamp null default CURRENT_TIMESTAMP );
Query OK, 0 rows affected (0.01 sec)

mysql> show create table temp3;                                       
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table                                                                                                                                                                 |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| temp3 | CREATE TABLE `temp3` (
  `id` int(11) DEFAULT NULL,
  `bleh` int(11) DEFAULT '1',
  `tstamp` timestamp NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)