Lightning Calendar - Organize your life — it’s about time!
Plan - Plan is a better way to organize.
Simple Calendar - A simple calendar with events (optional recurring and reminders), week numbers and a customizable...
Outplanr - Turn your to-do list into a real work plan
GMinder - GMinder is an open source Windows System Tray app that pops up to remind you about Google Calendar events.
Clean Google Calendar - Makes Google Calendar look nicer & launches as a desktop app