If you're receiving spam in Apple's Calender, here is a simple way to stop it, in theory, anyway. Just send it to your email account, and the spam filter there should move it to the Spam folder, where you'll never have to look at it. This method looks simpler than a procedure outlined in another article I recently sent out. Fortunately, I've not been bothered by spam in Calender. I'd guess Apple will eventually modify Calender to properly handle this issue.