tportal is a JSR168 compliant portal running on Google App Engine. Using Google API you can write your own portlet to display document on drive or manage your calendar event.
Still in development, you can try it on http://t-portal.appspot.com/
To clone and test it, you may need two files : client_secrets.json and client_secrets_local.json, see https://developers.google.com/api-client-library/python/guide/aaa_client_secrets for example
For the moment, there is still lots of stuff do do, but i'm working (slowly) on it..