Google Calendar - Spend less time managing your day & more time enjoying it
25DaysOf - A customizable advent calendar, for everyone
Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.
Frozen Goodies - An advent calendar to get the chance to win daily prizes
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Syndical - Automatically publish events across a range of platforms