What are the best cross-platform calendar apps?

Google Calendar has a monochrome base design that's accented with colored-coded events and image banners that separate months in schedule view.

The app has 5 different views - schedule, day, 3-day, week and month.

Day, 3-day and week views split up the days horizontally and hours vertically. Month view lays out all days in a grid and displays up to 3 events in a day.

Schedule view displays an agenda view that allows browsing all events by swiping vertically. Additionally, the way events are displayed in the agenda view is context-aware. For example, adding an event called "gym" will display the event on a background with a dumbbell.

All views except for month view can be split horizontally to display a condensed month view at the top that can be navigated by swiping horizontally.

Events can be added from any view by clicking the red plus button that's available at the bottom-right corner of the screen.