If you have used Google+ Hangout, than you must be willing to know if there are any public hangouts on Google+? The answer is Yes!, now you can search public hangouts on Google+ from this website gphangouts.
This website lets you search public Hangouts and you can also create a public hangout from this website. It also shows the recent hangouts.
Since Google+ is in its early phase, people are still playing with its features to know completely about the power of Hangout.
If you still are not aware with the features of Hangouts, View this video