Even in the age of smartphones I still prefer to check the calendar on my computer and I’ve often been disappointed by the horrible default calendars that ship with some operating systems (e.g. macOS’s calendar accessible via its systray).
Fortunately for us, Emacs users, we always have access to a proper calendar regardless of our OS and desktop environment (if any) - M-x calendar. By default it looks something like this:
Nothing fancy here, just a simple calendar that highlights the current date. You can easily jump to any date by pressing o (it stands for other) and go back to the current date by pressing .. You can also use < and > to move back and forward in chunks of 3 months (by default).
You might have noticed that the calendar by default assumes that the week starts on Sunday, although in many countries (Bulgaria included) it actually starts on Monday. You can easily change this: