A developer has managed to get Siri to control his home thermostat. The hack does not involve any jailbreaking but does involve setting up a proxy server which intercepts the Siri commands. This proxy server can then be used to add additional command functionality to Siri.
Siri Proxy is a proxy server for Apple's Siri "assistant." The idea is to allow for the creation of custom handlers for different actions. This can allow developers to easily add functionality to Siri. The main example I provide is a plugin to control my thermostat with Siri. It responds to commands such as, "What's the status of the thermostat?", or "Set the thermostat to 68 degrees", or even "What's the inside temperature?"
The developer has put together a video showing how the proxy server can intercept Siri voice instructions and then use them at a local level. In the demo, the developer asks for information from his room thermostat and Siri responds with the internal temperature and set point. The set point is then changed using Siri and sure enough, his thermostat is updated.
The demo is very impressive and does open up Siri to a whole host of possible uses. Home automation is the obvious area for it to expand into.