Hey Alex,
It looks like on that site, you're using an incompatibel version of jQuery, so the munchkin event is not firing. Munchkin.js only support version 1.3.* to 1.8.* of jQuery, so you'll need to either switch to one of those library versions, or switch munchkin-beta.js which has no jQuery requirement. You can do this just by changing the path in your munchkin snippet from 'munchkin.js' to 'munchkin-beta.js'.