FWIW, I just checked what the RationalWiki IP-edit captcha does: we're using QuestyCaptcha, which asks "What is the nth letter of our name under the logo?" (said name being of course "RationalWiki") - and this (a) utterly confuses the spambots (b) doesn't hamper accessibility.
Edit: Although of late we have a vandalbot written specially for us, which hops from open proxy to open proxy. So an arms race over the questions would be laborious - thinking of good new quesitions is slower than telling your bot how to deal with them - and our work is to find what proxy list he's using and inform the blackhole list operators of it.
Thanks, I've passed this to Trike.
It seems that if you look at the column on the right of the page, you can see upvotes and downvotes separately for recent posts. The same [n, m] format is displayed for recent comments, but it doesn't seem to actually sync with the score displaying on the comment. This feature only seems available on the sidebar: looking at the actual comment or post doesn't give you this information.
Thanks, whoever did this!