New registrations on a forum

[electrician]

Hi guys

I have a DIY forum and I get lots of funny users,bots and spam - I don't anymore which one is real or not.

How do I get a trick question like the one on this forum ( square red & black ) ? The forum is here http://www.robuild.co.uk/forums/

Thanks in advance
Regards

[jgetner]

your forum is phpbb software i would start looking there first