GNOME Calendar has gotten *so good*, it just handles ICS files, multi-day events, multiple calendars, and mismatched timezones so well now. Hands down my favorite calendar app on any platform. If there's a "most improved app award", surely it must be a contender.
Totally! I recently revisited GNOME after a long spell with KDE. Some apps, and Calendar in particular, have improved by a huge leap. Very impressive, and a big thanks to the maintainers.
Salcie