Google Calendar - Spend less time managing your day & more time enjoying it
SmartDay - Integrated organizer with automatic scheduling.
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Pocket Informant - Pocket Informant is the Best Calendar app for mac and iOS. Pocket Informant for iOS, Mac desktop, and Android.
Calendar Lock PEA - Calendar Lock PEA is an encrypted desktop calendar with a day, week and month view. The shown calendars are never stored unencrypted on your disk, but exist only in the RAM. Platform-independent, Open Source, no installation or registration required.
Morgen.so - All-in-one Calendar, Tasks & Scheduler. Morgen is the single hub for everything that revolves around time management.