Google Glass is finally expanding beyond the United States and opening up sales in the UK. If youre not ready to lay down that much cash right away, Google seems hopeful that a demonstration may sway you; The company will be setting up shop between 10AM and 8PM on Stable Street, and you can RSVP now to reserve your chance to sample Glass and chat with the Google employees responsible for creating it. Google launched its invite-only Explorer campaign last year, and in the months since Glass has proved equal parts promising and controversial.