Sure you've seen Siri work her voice recognition magic on an iPhone 4S, but how about on an older rotary telephone? Davis Remmel took a Bluetooth headset and retro-fitted a rotary telephone to have Siri work as an operator of sorts, catering to your questions and placing phone calls by dialing 1 on the phone.
Back in the day of rotary telephone, dialing 0 on a phone would connect you with an operator. You could ask that operator to call a certain person for you, for instance, "Call Bob Smith," and the operator would place the call. Siri can work in much the same way. Saying "Call Bob Smith" into an iPhone 4S with Siri enabled will in fact dial Bob Smith (assuming his contact info is store on your phone).
For this hack, Remmel took apart a Bluetooth headset, placing its earpiece in the earpiece portion of the rotary phone, and the microphone in the mouthpiece. Dialing 1 on the phone activates Siri on Remmel's iPhone 4S (which is connected to the rotary handset via Bluetooth), and allows you to talk into the rotary phone and perform actions on the iPhone. Since the rotary handset is now essentially a Bluetooth headset, once you place calls you can actually hold a conversation through the rotary phone as well.
While it's not the first Siri hack we've seen (check out a man start his car using Siri), it's certainly pretty impressive. You can learn more about how Remmel was able to put this hack together on his personal website.
Curious what a Siri-enabled rotary phone looks like in action? Check out the video below.