I am going to repost what I just posted on Slashdot in response to the same question:
There is a cheaper option
Instead of paying $1500 for Google Glass, why not make your own!
You'll need an old pair of sunglasses, a piece of cardboard, sticky tape and a felt-tip pen.
Remove the glasses from the glass frame, write "Punch Here!" on the cardboard and tape it to the upper part of the frame above the eyes. Ta da!