@skeevis We figured it out -- if you're already in direct message with @foo I don't think that you can /insult @foo. Once we tried using it on open channel it worked great, my coworkers are having a field day.
I've been fascinated by the growth of bots, and since we use Slack internally at @contactually - I figured it was worth a weekend experiment to work with the API. And why shouldn't the world have a bot that allows you to throw Shakespearean insults at you coworkers!
Internal Server Error
.