First off , OMG Nick!
I don’t visit lots of different forums, even so I’ve never seen anything like that. I haven’t tried to register at your site, just did a quick tour. My suggestion would be registration with security images same for posting messages, you know those hard to read pictures of numbers you’ve gotta copy before you can submit something.
For some CMS’ there are free and easy to implement modules available. It won’t help againt human spammer but will make it harder for bots.
For Lady Hold’em,
Are you using a registration system which requires an email confirmation/check coupled to a time delay so you can check applicants?