For those who haven't noticed it yet, Google has gifted a "cheap version" of the "oculus rift" to the attenders of its IO event. Also, they have published the instructions for the rest of the planet in this webpage https://developers.google.com/cardboard/ As you may read, the only difficult-to-find component are the lenses, these 40mm focal length x 25mm diameter bi convex lenses are out of stock in Europe. BUT I found an american webpage that sells them, here you are. http://www.surplusshed.com/lens.cfm Awesome Google :) EDIT: Found another one with all the load packed together http://www.dodocase.com/products/google-cardboard-vr-goggle-toolkit
...so keep it simple