Waterloo Labs has devised a way to play NES games using eye movements. Simply put, it's pretty awesome. Their custom-made setup uses electrodes and a bunch of technical stuff I cannot begin to understand to amplify and redirect the signal to the console.
This is clearly a fun project, but there's much more serious potential for it when you begin to think about disabled gamers, and how the concept could be adapted for them.
Here are some comparison shots for the Smash Bros. and Mario Party amiibo lines
1:30 PM on 03.09.2015