Ref: http://code.google.com/apis/accounts/docs/OAuth2InstalledApp.html
For local applications
- Show user the page (modify as needed):
https://accounts.google.com/o/oauth2/auth?response_type=code&client_id=YOU_CLIENT_ID&redirect_uri=urn:ietf:wg:oauth:2.0:oob&scope=https://www.googleapis.com/auth/calendar