My Calendar - adding an event

Does anyone know if you can add an event (non-Viking) onto the My Calendar? We are taking an outside shore excursion and I want to add it. It would seem that this should be a functionality the site should have so guests could add things like: "Dinner with the Joneses" or "Order birthday cake for Sue". Any ideas?

As far as I have been able to tell and unless they have recently updated its functionality, the MVJ is self-populating, fed by shorex, dinner reservations and spa appointments only, and has no way of manually adding anything or of syncing with any other calendar.