Google calendar syncing problem
I had similar problem. I had to clear calendar cache - than re-sync worked for me. 
The cache clear method is very similar like in this answer, but I clear the official Calendar storage:

Go to Settings -&gt; Applications -&gt; Manage applications. In the top of the screen select All. Scrool down to Calendar Storage, then open it, tap to Clear cache button. 
Re-sync (Google) Calendar. You're done.

Maybe you have no Calendar Storage app, than I sorry, I have HTC Wildfire.