Instead of your run-of-the-mill alphanumeric gibberish, or random selection of words, the Civil Rights Captcha presents you with a short blurb about a Civil Rights violation and asks you how you feel about it. Ostensibly robots (and trolls) won't make it through because they'll remark that a human rights activist's murder makes them feel "aroused" instead of "upset." And bots will still have to make it past standard Captcha hurdles before they can even pick one of the choices.
Code for the Civil Rights Captcha is freely available, so anyone who wants to can pick it up. It definitely makes better use of Captcha space than most traditional systems do, and it's an interesting take on a system; isn't empathy more exclusively human than text recognition? And so what if the robots learn to fake that. It could make the robopocalypse so much more comfortable for all of us. More here.