I found a solution today. I was cruising some forums looking for an answer, and found one here. The following is how I did it:
If you have events saved to the "My Calendar" (the device's calendar), you will lose them using the following procedure. I don't use the device calendar, so I wasn't worried. You may also want to check from within calendar itself that all the calendars you have are selected to show up (From within Calendar, hit Menu->Settings->Calendars, and verify that all your calendars are showing and checked. Mine didn't even show up). A final caveat would be that if your phone is not syncing email, it may be a deeper sync problem than this calendar issue.
If your problem passes the above caveats, here are the instructions for the fix that worked for me:
- Go to Settings->Applications->Manage Applications. It may take a while to load the Manage Applications part.
- Select the "All" tab (because Calendar is bundled with the base system) and scroll down to where you find Calendar. Select Calendar, and tap "Clear Data". I also did this for "Calendar Storage" and "Calendar Sync Adapter" but I don't know if those are necessary (up for comment discussion).
- In then rebooted my phone. Also not 100% sure if that is necessary, but it didn't hurt in my case.
- When I booted back up, the calendar started syncing and my events started showing up (and I have a bunch of calendars--it worked for all of them).
I was very pleased to find a solution to this problem, because part of my reasoning behind having a smartphone is the calendar feature. I haven't been too excited with Android's calendar, but this was a real downer. I am very glad to have it back to normal.