You can now join Google+ hangouts directly from Google Calendar - TechHive Beta Blog

Monday, September 3, 2012 11:00 AM Here's a small but useful addition for you Google+ users: You can now use Google Calendar to schedule Google+ hangouts, and easily join them with one single click. If you use regularly use Google+ hangouts for business meetings or social get-togethers, this new feature is going to make setting those up a whole lot easier.

http://pulse.me/s/cWi80