Press your device's < Home > button, then press < Menu >.
- Select Settings.
- Select Applications, then Manage applications.
- Select Calendar Storage.
Note: If you don't see 'Calendar Storage,' press < Menu > again, then select Filter > All. On some devices, you won't see 'Calendar Storage.' It is fine to ignore this step if it doesn't apply.
- Select Clear data. Answer OK when prompted.
- Restart your device. Press and hold the < Power > or < End call > button, then select Power off. Press the < Power > or < End call > button to power on.
The important thing here is to turn off the phone right after clearing the data. I tried "clear data" and then "Force Stop" as recommended on other blogs - but that didn't seem to work. The power off worked first time.
My problem was that in the calendar menus I could only see my calendar (the phone one) and a single google account reference (my google account) - and when creating an event I was only offered one of my google calendars as a choice for putting the event on. After the fix I still only saw the google account in my calendar list (other android phones have shown each calendar within my google account) - but when I created an event I was offered a choice of all my google calendars.