Facebook reported yesterday that they are new Events API calls that will:
"...allow applications to create, modify, and cancel events, as well as submit a user's RSVP to any event that the application created.
With an active session and the appropriate extended permissions, your application can manage your users' schedules for any events created through your application. These events appear on their profiles alongside all their other events, so they can easily keep track of what's coming up as well as invite more friends. Applications that could take advantage of this include those that manage personal events and those that host events."
They've also updated the events APIs to be sessionless as well.