Back in the NES days, Nintendo offered up a controller that, chances are, you've never heard of before. It was the Hands Free, and it was designed for the disabled.
The Hands Free was a huge controller that was strapped to the user's chest. The D-pad was controlled by the user's tongue, while you could control the A and B buttons by blowing and sucking through the pipe. I'm not quite sure how you could hit both buttons at once, but I'm sure they made it usable.
Back when it was released in 1989 it retailed for $179 straight from Nintendo, but if you want one now you'll have to hit up eBay, where they go for upwards of $600. [Kotaku]