I have a number of Google calendars open on my phone. Sometimes I add things to wrong one. I can't see a way of moving items on the standard application. Does any other Calendar app gave this feature?
Business Calendar Pro (and maybe even the free version) can move events from one calendar to another, even if they are on different accounts. I got Business Calendar Pro when I was still using the Samsung TouchWiz UI because I did not like their calendar application. Now that I am on a Vanilla Android, I still use Business Calendar Pro. The agenda widget is nice and the UI and functionality exceeds the stock calendar app.
There is also an excellent (swiss made) app for bulk operations with events across all available calendars (including the local one): move, copy, delete. The events can be filtered by a lot of parameters:
Copy Calendar Events Pro