You can easily backup your Google Calendar by downloading (exporting) your calendar, but how do you backup your Google Tasks data? This stumped me as there does not seem to be a way to do this in the same easy way as with your calendars.
Here’s my solution, I have Mozilla Thunderbird installed for testing (I usually use the Google Apps web interfaces for doing email/calendar etc.). So I figured I’d pull the data to a local source (Thunderbird) which is then backed up normally with all my other local files.
To do this I installed an additional two plug-ins for Thunderbird, Lightening – calendar plug-in and Google Tasks Sync – which does what it says on the tin. Setting up Google Task Sync is painless and once you authorised the plug-in it pulls your tasks in and viola, tasks backed up! The plug-in is GPL licensed too which is a big plus.
From the plug-in page:
Utilizing the Google Tasks API, this add-on allows you to manage your tasks directly from Thunderbird. If you are online, any changes you make are synced immediately. You will be notified in case of a sync error, so if that doesn’t happen, you can be sure your tasks are up to date. If you are offline, you still have full functionality, and the changes you make will be synced once you’re back online.
In addition, all your tasks are backed up locally once per session. The last 10 backups are stored and can be accessed with a simple viewer located in the add-on’s options.
This add-on is designed to complement Lightning (which can sync events with Google Calendar, but not tasks). However, it does not require Lightning to function. If Lightning is installed, Google Tasks Sync’s interface can attach to the Today Pane.