This calendar uses an app called event brite, not sure if you've heard of it?
It looks like clients can choose to pay through the site and it give you the option to pass the fees on to the clients or absorb the fees your self.
This calendar syncs events on the google calendar. I've used one of the alias accounts we created.
Another alternitive calendar
This is the calendar we currently use, it looks like we can play around a bit with the colors and fonts