Just made a little jQuery plugin: http://github.com/zef/jquery_form_toggle It makes it easy to show and hide elements based on the state of a checkbox, radio button, or select menu. Demo: http://madebykiwi.com/files/jquery_form_toggle/ I'd be surprised if there isn't something like this out there already, but I couldn't find one. If you have a suggestion for a better name, I'd be happy to hear it.
chide? It's a real word, but also mix of checkbox and hide.