Lance from DE asks:
Is there any way to get my Google Calendar to show up in Mozilla Thunderbird?
Thunderbird  is one of the most used desktop email clients out there. With all of its functionality, it’s a definite choice for just about any email task. Google Calendar, on the other hand, is a feature-rich web-based Calendar application that, if added to Thunderbird, will help you enjoy best of both worlds. However, Thunderbird does not come with a built-in Calendar. So here is a step by step guide to add Google Calendar to Thunderbird.
1. Fire up Thunderbird and go to Tools > Addons. Once you are there search for Lightning.
2. Once you find it, use the install button to add it to Mozilla Thunderbird. You will need to restart Thunderbird to complete the installation.
3. You will now see a new label Events and Tasks in the Thunderbird menu bar.
4. Now, in a similar way, install another extension called Provider for Google Calendar 0.8 to allow bidirectional access to Google Calendar. Search for the term Google Calendar in the add-on tab to find it.
5. Now log in to your Google Calendar account in any browser. Go to Calendar Settings.
6. Go to the Calendar tab and click the calendar you wish to add to Thunderbird.
7. Scroll down until you reach the Calendar Address section. You will have three options to copy the address of your calendar. Right-click on the XML option and copy the link location.
8. Now in the Thunderbird window, go to File > New > Calendar.
9. Choose On the Network and proceed. In the next screen, choose Google Calendar and paste the calendar address you copied from your Google Calendar settings (step 7).
10. Press Next and you will be prompted to enter your Google Calendar username and password. Press next and name your calendar, choose a color and opt to show the alarms.
Now that Google Calendar is added to Thunderbird you’ll never need a separate tool to keep track of your events or emails.
~ Soumen Halder