I finally out two and two together to figure out how to control my Philips Hue lights with Siri thanks to IFTTT!
IFTTT allows you to text the service and allow certain hashtags to cause certain triggers. So I simply created a contact with the name “Philips Hue” using my IFTTT SMS number. Then I tell Siri, “Tell Philips Hue to turn hashtag off,” or some such phrase. Boom! The lights turn off. Check out the recipe below!