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.

Calendly - Say goodbye to phone and email tag for finding the perfect meeting time with Calendly. It's 100% free, super easy to use and you'll love our customer service.

GMinder - GMinder is an open source Windows System Tray app that pops up to remind you about Google Calendar events.

Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.

Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...

SavvyCal - A scheduling tool both the sender and the recipient will love.