If you use the Bad Behavior antispam plugin, and your WP install just locked out you and your friends and your load balancer itself, it’s because of this:
http://www.bad-behavior.ioerror.us/2007/12/06/bad-behavior-2011/
Area Bad Behavior Software Shows Bad Behavior.
Upgrade or face doom.
thanks.
I think I was using a pretty old version, anyway.