Lightning Calendar - Organize your life — it’s about time!
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
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.
GMinder - GMinder is an open source Windows System Tray app that pops up to remind you about Google Calendar events.
UKs Kalender - This program helps you organizing your dates and tasks and reminds you of upcoming events.
SSuite My Calendar Diary - A portable calendar and diary for people on the move...