I play in <i>cough</i>Dungeons & Dragons<i>cough</i> games in Hangouts and this looks tremendously useful.<p>The participants are usually spread out across the world... the option to view Hangout times in in terms of local time would be _excellent_.<p>Secondarily, the ability for the organizer to review the attendees' local times for each proposed timeslot would be great too. It'd be nice to know that your timeslot wouldn't be 3am for half the attendees.
Another good feature would be to make the event open so people could enter their details to register. At the moment, the organiser still has to use another channel to ask "who's in?" and collect e-mail addresses.
Slick! How about a "quick create" option, like in Google Calendar? That's how I create all my Calendar entries, though your average user is probably more adept at mousing than free text entry :P