Contact form captcha

[kenfuzed]

Anyone know of a hack/mod to add a captcha or other verification to the contact form in vB? I constantly get emails from idiots selling warcraft junk or floods of links from asian electronic sites.

I need to keep the contact form available to unregistered users since it really helps those with login problems, but it would be nice to verify it's a human and not a bot. I've also noticed that adding IP addresses to the banning option doesn't keep them from spamming my contact form.

[Mike54]

Admin CP > vBulletin Options > Site Name/URL/Contact Details > Allow Unregistered Users to use 'Contact Us' > Yes, but Verify Image > Save