How to unblock my own admin account after 5 failed login attempts? I entered the wrong admin password more than 5 times, so Drupal has blocked my entry.

I've change the user password directly in MySQL and then tried to login, but is still doesn't work. Also, if I click the request new password link, I don't get an e-mail. 

How can I unblock my account?
To answer the question in your title (which appears to become more complicated following your actual question), you just need to clear the flood table in your database.  If you're running Drush, then the following should sort you out:


  drush php-eval 'db_query("DELETE FROM flood");'


Failing that, just clear the flood table from your database manually :)