How about combining these...

[DetlefK]

1. A device that lets you control a computer with gestures. An armband worn around your lower arm reads the movements of your hand- and finger-muscles.
https://www.thalmic.com/en/myo/

2. Google Glass delivers a screen right in front of your eye.

If you combine them, you no longer need spoken commands or twitching or winking to control your Google Glass: Four fingers are the "arrow-keys" and control where the cursor is going. (So, if somebody shows you the middle-finger, don't get angry: He might be scrolling upwards in a document.) The thumb is the "double-click". If you add your other arm and hand into this, even more complicated gestures and commands are possible. All commands could be as subtle as wiggling a finger.

[tridim]

1. I've always wanted to control my computer like playing chords on a guitar.

But the screen and controller will be installed inside your brain in 10 years anyway.

[DetlefK]

2. More like 30, by my estimate.

[Igel]

3. LeapMotion.

It's like Kinect, but smaller and attaches with a USB device. Easy to calibrate. Don't know how reliable it is--I don't have a computer that's fully compatible with mine.

It's a class of new interface devices called "gesture controllers."

Interfacing the gesture controller with something as small as Google Glass, which is really a stand-alone stripped down device, may be dicey.