We missed this little gem over the Christmas break but it's worth passing on for the Google heads out there. The Google Operating System blog has written up a guide for creating a "backup" for your various Google accounts - both to archive material such as Gmail but also to provide an alternative account if you can't access your main account.
If you create a "backup" Gmail account, you can set up Mail Fetcher in the backup account. You'll need to add the main account as a custom From address - then you can check or send messages from the "backup" account if needed.
You can configure your Google Calendar to let you view and update it via your "backup" account. Click on "Manage calendars" at the bottom of the window, share the main calendar and add the backup account. You should select "make changes and manage sharing" from the drop down menu.
And you can add the backup account as a collaborator for your important Google Docs and Notebooks.
There are a number of nifty tricks for providing yourself with backdoor access to your Google accounts - the article also covers how to enable sharing to provide 'backdoor' access to Blogger, Google Analytics and Google Groups.
"The backup account will not have all the data from your main account, but you'll still be able to read your email, send messages, post blog posts, check your calendar, add new events, access important documents etc."
Creating a Backup for your Google Account [Google Operating System]