Today I received weird Google calendar notification in Russian from my email (or at least, it tricked my phone so that it showed my name as sender). The invite contained an email address from Turkey. I have no idea of what it said as it was in Cyrillic.
I have now found out this is a new phishing technique that plants malicious links in your google calendar.
Important settings in Google Calendar can help you prevent this sort of thing. This article by Wired explains it all.