Funny Internet Spam for eMail and Websites is Spicy
FluxBB: anti-spam alternative to CAPTCHAs and HoneyPots

Prior to anything this should be very clear from the start: CAPTCHAs and/or HoneyPots are commonly used, really efficient techniques to counter spam on forums. The point here is not to encourage not using these techniques, but to provide a quick and simple technique I’ve been using for years and that proved to be working…