Microsoft Kinect is a camera based gesture controller with high-quality speech recognition first released as a Xbox 360 video game peripheral and then in a slightly more advanced and expensive desktop version for PCs.
Kinect enables control of, or informal interaction with, computers and consoles using physical movement and gesture alone - also notable is that voice recognition can be used for media access out of the box on Xbox 360, making it an attractively-priced assistive technology solution for some disabled users.
Much of the focus of developers of free software has been on the cheaper Xbox 360 controller - which also works well with Windows and OSX desktop computers.
The Kinect SEN Wiki below is a great starting point and provides up to date news, free software and tutorials for teachers and others working with people who have developmental disabilities
Using Kinect and (mostly) free software in special schools
Somantics is a suite of sensory, cause and effect interactions developed for students with complex needs
Case studies on the use of Kinect with special needs students from Kinect SEN
Microsoft's Kinect for Windows Site
Little Angels Special School Pinterest board on Kinect and Autism
Visikord is commercial VJ software winning fans in special education - free trial downloads are available.
Kinect and other interesting tech applications in special education