Based on the [previous link][prev] to a Node.js -> Arduino bridge, [@JerrySievert][guy] pointed me to [his own take: An event-driven package for Arduino/Node.js][link]. Listening for events on the board itself is a really cool idea.
[link]: https://github.com/JerrySievert/EventDuino “JerrySievert/EventDuino”
[guy]: http://twitter.com/JerrySievert “JerrySievert on Twitter”
[prev]: http://extrafuture.com/2012/06/07/arduino-and-the-web-using-nodejs/ “Previously: Arduino & the Web using Node.js”