Recently Google announced the offline access to Gmail, which is very much useful when you are travelling and you don’t have internet connection. Google goes one step ahead and not enabled offline access to Google Calendar. While you're travelling or without a strong internet connection, you can now see your Google Calendar events when you're disconnected.
Offline Calendar lets you view your existing schedule and events, but not edit them, so you don't have to print out calendars the night before a trip. This feature has been available to businesses and schools using Google Apps for about a month; Google is now turning it on for everyone.
Like Gmail, the offline feature of Calendar uses Gears, an open source browser extension that adds offline functionality directly to the browser.
To enable offline Calendar access, sign in to Google Calendar and look for the "Offline Beta" link in the upper right-hand corner of your account, next to your username.
Google has released this early and are still ironing out some kinks, so there are chances that you may encounter some issues. If you access Calendar through the Premier or Education Editions of Google Apps, your domain administrator will first have to elect to turn on new features from the Domain Settings page of the Google Apps control panel.
There are multiple ways to see your calendar when you're away from your desk — in addition to offline mode, Google offers two-way sync for iPhone, Android, Windows Mobile and Blackberry devices. So wherever you go, Google Calendar can be there with you.