I got one for you. Someone from Brazil figured out that our network admin didn't have all the ports locked on our server and bounced a heck of a lot of email off it one morning before we found what the slowdown was. We got about 8k undeliverables back in our mailbox in just a few hours which is what tipped us off. The really interesting thing was that the emails went out with the law firm's email address as a reply. They were of course 'enlarge this' or porn site emails. heheheheee, boss loved that one. (NOT).