From a technical standpoint, this should not be difficult to do. So much so, that it probably falls within the abilities of the API, and won't see much attention from the developers. I managed to work something out with the API to create a time of day visible to my players, that I could edit with relative ease. It's not perfect, but it's a work in progress. The basic idea is that I have a Macro that is available to the players, and they can have visible in their macro bar. I use the API to change the name of the macro to the current time of day - this means that everyone has a little clock in the corner of their screen. I then added some functions to adjust the time, and gave myself a macro that prompts for "Hours" and then "Day's", stores those numbers, and then changes the clock macro name accordingly. Then I added in a function that adds a given number of minutes and correctly formats the time when you exceed 59, and gives a leading zero, etc. With all that in pace, I can add a macro that adds 10, or 20, or 60 minutes. My code isn't in an amazing state to share, but if you have API access it's not that difficult to do. The main trick is using a macro name as a display for your clock, and then setting up functions and macros to adjust it. I didn't need a full calendar for my purposes, but adding that sort of functionality should be simple enough. The down side, of course, is that it's not pretty. And that's where this suggestion requires something that can't already be done: Adding arbitrary text and graphics to the interface. Obviously, a nice easy to use calendar and clock control would be much better, especially if we could customize the way it displays. My method won't give you an analog clock for instance, just text (well, you can use an Emoji clock for hours...), and it's very small text at that. But I think the real missing feature here is a more robust way to display information from the API, and a more robust user interface for interacting with the API.