Arcana's Calendar Broker is a LibDataBroker addon that allows the player to view pending calendar invites and access the in-game calendar. It was designed to be extremely simple.
This addon requires a LibDataBroker Viewer (such as ChocolateBar) so the user can see the information.
I wrote this addon after finding no LibDataBroker-compatible addons that allowed me to access the calendar quickly and easily without having to install other modules. This is essentially a feature-light version of FuBar_CalendarFu.