Google+ has unrolled another feature related to Hangouts this week. Now you can create a Hangout from Youtube and watch any video with your friends. Previously it was only limited to Live video streaming but now you can enjoy any Youtube video with your friends in a Hangout.
To Start a Hangout From Youtube
# Open any video on Youtube, Click Share button under the video
# Some options will open under the share button, on the right side, you will find option to"Watch with your Friends. Start a Google+ Hangout"
# Hit on that, and you are ready to enjoy that video with your friends.