You can access The Perfect Circle guild raiding calendar online through the World of Warcraft armoury. I cannot link directly to the calendar here because it requires you to log in, and the URL includes your character name.  So for Khal, the URL would be:

http://eu.wowarmory.com/vault/character-calendar.xml?r=Dunemaul&n=Khal

You can access the calendar for your character by replacing 'Khal' with your character name.  Alternatively, you can follow the steps below and bookmark the calendar page.

Step 1) Login to the armoury, by visiting:

http://eu.wowarmory.com/guild-info.xml?r=Dunemaul&n=The+Perfect+Circle&p=1

And selecting 'Log In' from the top right of the page:

Step 2) Enter your World of Warcraft account details, and you will be returned to the guild armoury page.

Step 3) Click on your characer name in the top right corner of the screen to visit your character armoury page, eg:

Step 4) Click on the 'Calendar' tab to view the raiding calendar for your character, eg:

At this point you can see the raid calendar for your character, even accept or decline events!  You can also bookmark the page in your browser so that you can visit it again easily in the future.