Software to maintain a daily routine with a popup / balloon popping up from the tray?

Question

Task Management

I am looking for the second day of software, from which the only functionality is required, that to have a certain daily schedule and according to this schedule, so that a reminder pops up unobtrusively in the tray, which itself will hide (like notifications in thunderbird / skype pop up), after half a minute it disappeared . You can unobtrusively softly click.
The schedule is as simple as a traffic jam, only slightly different on weekdays/weekends. Calling, writing emails, integrating with the browser, offering to buy an elephant and blocking the ENTIRE screen with a reminder interfering with work - nafig is not necessary.
Maybe someone will tell? Especially if there is something cross-platform, open and with screenshots

Answer 1

Outlook, Google Calendar. Yes, in principle, probably any online calendar + CalDAV client to it. Pop-up notifications - work through Desktop notifications.

Answer 2

Leader Task