Are you looking for a way to monetize your calendar?
EventPromote is off and running!
You can now have the ability to collect money via your frontend (post your event) button.
You could charge for featured status, allow images, show their ticketing/registration link, or any other promotional/sponsorship packages you want to make available.
People are most likely to pay to promote their event when they are on your sites posting. Help them create a successful event while creating a new revenue stream for yourself.