A rumor is spreading that Apple will be making a new device that curves around your wrist, which is fully Siri supported. Apple believes Siri should be ready to fulfill your commands instantly rather than going through the hassle of taking your phone out of your pocket. Apple also wants the devices to be a part of you rather than just "with you".
This is still a rumor and some information is still unclear such as to whether you need an iPhone 4S in order for the device to work. It doesn't just serve as a Siri device, but will also be able to give you notifications such as an incoming call or when an event is coming up.
It has also been rumored that Google is working on their own wrist-wrapping device (which may conclude that the Apple rumor is true).
In the future, I think this device will also have the ability to attach itself to your skin permanently, to read your thoughts and inject molecules into your blood stream to control your feelings towards competitors and always using useless devices from Apple.