Google has finally revealed the function that you recently requested users. Now all the information from your Gmail calendar and Google Calendar can be downloaded to your hard drive or directly import to another service.
Zip archive is saved as MBOX. Information downloaded entirely optional – you can choose exactly what you want to export.
New feature will be part of the project Google Takeout . Currently it allows you to upload your archive video from YouTube, location history in Gmail, Google Chat logs and Hangouts, tape Google+, contacts and more.
Note that at the moment content downloading Gmail yet available, although the “Calendar” in the list of already added. Google promised that this situation will be rectified soon.