The Boston Ruby Group will be streaming live via Google Hangouts on Air
reefpoints.dockyard.com
reefpoints.dockyard.com
I personally didn't think much of it until I started running into various people and groups hosting sessions. For instance, just this past Tuesday, the Transit of Venus was occurring, and a group of professional astronomers[1] hooked up multiple camera feeds from powerful telescopes, and discussed all sorts of topics in science, and took questions from viewers.
It started gaining viewers until one of the casters was pulled off for an interview by the Guardian, and then Natalie Villalobos [2], one of the Google+ Community Managers showed up, and just started chatting with the guys about how the Hangout is going, and how popular it is, as well as her personal interests in astronomy, etc [3].
It was informal, informative, and the first example of compelling usage for the "On Air" feature I have witnessed. I can only imagine many more good things come out.
[1]: http://youtu.be/t79iec2b-3M
After some more experience with running BostonRB's meeting over hangouts I'll follow up with a blog post on what we have liked and what pain points we've had.