StopDesign have some intersting tips for Google calendar, an excellent resource with almost all you need to do, and all things you don't know. You might also check my Tutorial on how to integrate Google Calendar in your website using AJAX, if you are interested into showing your events from Google calendar into your website or community. Tips by StopDesign include :

1. Keyboard shortcuts
2. Customized view
3. Reminders as text messages to your phone
4. Get daily agenda via a text message
5. Mac only: Lack of Safari support
6. Mac only: Camino works too
7. Eliminate browser chrome
8. Keyword access
9. Syncing
10. Mac only: Smoother text for times
11. Privacy and security
12. Firefox extensions
13. Miscellaneous

Since I’ve been an early user of Google Calendar for a few months now, thought I’d share a few tips that may make the jump a little smoother for others. Some tips may seem obvious, other tips may be completely new to you. Specifically, I’ve noticed hesitation by Mac users in trying Google Calendar, which I’ll address in a few Mac-only tips sprinkled in with the rest.