Google also demonstrated its futuristic, Internet-connected glasses by having parachutists jump out of a blimp hovering about 7,000 feet above San Francisco. 

The audience got live video feeds from their glasses as they descended to land on the roof of the location of the conference.

The prototypes of Project Glass are available to test. They can only be purchased — for $1,500 — at the conference this week.

If all goes well, a less expensive version of the glasses is expected to go on sale for consumers in early 2014.

Without a price for the consumer version, Google co-founder Sergey Brin made it clear the glasses will cost more than smartphones.