Image Credit: AP Photo/Paul Sakuma

In a surprising “one more thing” moment near the end of Google’s I/O Keynote today, Sergey Brin came on-stage to show off Google Glass, the wearable computer prototype announced back in April.

In one of the craziest PR stunts ever pulled off, Brin used the glasses to conduct a Google+ Hangout with a friend who dived out of a plane and landed on the roof of the Moscone Center, all of which was broadcast live to the keynote audience inside. Seriously. The Verge has video.

The Google Glass fun didn’t stop there. Brin also announced the “Glass Explorer Edition”, a prototype version of the glasses available exclusively to U.S.-based I/O attendees. Preorders start today at the low price of $1,599 for delivery early next year. As Brin noted, the Explorer Edition being made available to developers is a prototype, so it will be “rough around the edges”, and it is definitely not ready for consumers yet.