In order to prevent more of the kind of spam that occurred over the weekend, I'm now requiring each user to have their first few posts to these forums approved. However, once you have had three posts accepted you can post without restriction.
Sorry to do this, but it should save me coming home from a weekend away and finding the forums full of junk.
I've also added new fields to the forum registration process, the first of which asks if you are a spambot or a real user. Obviously they're easy for any human (including a spammer) to get around, but hopefully this should slow down the bots.