Project Glass is a research and development program by Google to prototype and build an augmented reality head-mounted display. This isn't a new idea, but Google seems to be getting loads of attention for their design as it appears to be quite small and attractive and they've released a pretty impressive promotional video...

I think this is pretty cool, but I don't expect this to become mainstream any time soon. That said things might just hot up when Apple or Microsoft enter the same domain, though Microsoft would need to improve on their user experience as everyone imagines it would be just like this parody video...