Good idea, but the demo site is down right now :(. http://wiki.dlang.org/extensions/DCaptcha/demo.phpAh, fixed. Broke that when I updated to the easy version.
Nice one, failed the first try :).You should probably reload on failure, or maybe only after the 3rd attempt or so.
Looks like you ruled out at least half of the spammers. http://blog.codinghorror.com/separating-programming-sheep-from-non-programming-goats/